EXCHANGE 


231920 


THE    SYNTHESIS    OF    MONO-AMINO 

FLAVONES,    OF    FLAVONE-AZO-BETA- 

NAPTHTHOL    DYES    AND    OF 

OTHER    FLAVONE 

DERIVATIVES 


DISSERTATION 

SUBMITTED  IN  PARTIAL  FULFILLMENT  OF  THE  REQUIREMENTS 

FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY,  IN 

THE    FACULTY    OF    PURE    SCIENCE    OF 

COLUMBIA    UNIVERSITY. 

VI^^YX 

ot  r»>" 
TV  H  R8i  T  V$ 


" 


BY 

JOSEPH  K.  MARCUS,  B.  A. 

New  York  City 
1918 


CHAUNCEY   HOLT    COMPANY 

227-239  West  17th  Street 

New  York 


THE    SYNTHESIS    OF    MONO-AMINO- 

FLAVONES,    OF    FLAVONE-AZO-BETA- 

NAPTHTHOL    DYES    AND    OF 

OTHER    FLAVONE 

DERIVATIVES 


DISSERTATION 

SUBMITTED  IN  PARTIAL  FULFILLMENT  OF  THE  REQUIREMENTS 

FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY,  IN 

THE    FACULTY    OF    PURE    SCIENCE    OF 

COLUMBIA    UNIVERSITY. 


BY 

JOSEPH  K.  MARCUS,  B.  A. 

New  York  City 
1918 


CHAUNCEY    HOLT    COMPANY 

227-239  West  17th  Street 

New  York 


TO  MY  PARENTS 


451718 


ACKNOWLEDGMENT 

The  author  is  indebted  to  Professor 
Marston  Taylor  Bogert  for  his  kind  encour- 
agement and  guidance  in  carrying  out  this 
work. 


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ABSTRACT  OF  THE  DISSERTATION 

1.  What  was  the  object  of  the  investigation? 

2.  To  what  extent  was  the  object  attained? 

3.  What  contribution,  actually  new  to  the  science  of  chem- 
istry, has  been  made? 


1.  The  intense  yellow  color  of  some  of  the  naturally 
occurring  hydroxy  derivatives  of  flavone  *  (certain  of  which 
are    valuable    as    dyes;    i.    e.,    Quercetin-l^S'^'jalpha-penta- 
hydroxy-flavone — in    Quercitron    Bark,    and    Morin — 1,3,2',4', 
alpha-penta-hydroxy-flavone — in  Old  Fustic)  made  it  seem  of 
interest  to  extend  the  investigation  of  the  flavone  series  to 
the  preparation  and  study  of  the  amino  derivatives  in  order 
(1)  to  record  the  auxochromic  effect  of  the  amino  group  on 
the  flavone  nucleus ;  and  (II)  to  couple  the  diazotized  amines 
with  betanaphthol,  thus  incorporating  the  flavone,  azo  and 
naphthalene  chromophores  in  one  compound,  with  the  hope  of 
obtaining  red  or  blue  dyes.     Further,   (III)   a  method  was 
sought  for  making  flavone  or  flavone  derivatives  which  should 
be  dependent  on  the  use  of  easily  available  materials  and  of 
few  reactions. 

2.  (I) — 2/-Amino-flavone,  3'-amino-flavone,  and  4'-ami- 
no-flavone  were  synthesized  by  the  reduction  of  a  mixture  of 
nitro-flavones  resulting  from  the  nitration  of  flavone.     The 
positions  of  the  amino  groups  in  these  amines  were  determined 
by  converting  them  to  the  corresponding  phenols.     Two  of 
the  phenols  obtained  were  identical  with  3'-hydroxy-flavone  5 
and  4'-hydroxy-flavone  *  (both  previously  prepared  by  St.  v. 
Kostanecki).     The  third  phenol  was  found  to  be  2'-hydroxy- 
flavone,  and  constitutes  the  sixth  of  the  eight  possible  mono- 
hydroxy-flavones  to  be  synthesized.8 

These  three  amines  are  all  yellow,  in  contrast  to  the  cor- 
responding hydroxy-flavones  which  are  white.  4'-Amino- 
flavone  possesses  the  noteworthy  property  of  imparting  fluores- 
cence only  to  neutral  solvents,  which  contain  the  hydroxyl 
group. 

(II). — 4'-Amino-flavone  was  diazotized  and  coupled  with 
beta-naphthol,  giving  flavone  (4')-azo-beta-naphthol  **  which 
dyed  silk  and  wool  a  fast  bright  red  color.  Flavone  ('')-azo- 
beta-naphthol  **  and  flavone  (3')-azo-beta-naphthol  **  were 
synthesized  in  similar  manner  from  2'-amino-flavone  and  3'- 
amino-flavone  and  gave  fast  orange  shades  on  silk  and  wool. 

*  See  structure  I. 

**  See  structures  II,  III  and  IV. 


(III). — 2-Nittb-fiaVaftcme l  -was '•  synthesized  directly  from 
para-nitro-phenol  and  beta-brom-hydrocinnamic  acid,  but  in 
poor  yield. 

Other  compounds  which  have  been  synthesized  for  the 
first  time  are: — 2'-acetoxy-flavone,  2/-diacetyl-amino-flavone, 
3'-diacetyl-amino-flavone,  4'-diacetyl-amino-flavone,  beta-phe- 
noxy-hydrocinnamic  acid,  the  barium  salt  of  a  disulfo-deriva- 
tive  of  beta-phenoxy-hydrocinnamic  acid,  beta-ortho  (or 
para)-hydroxy-phenyl-cinnamic  acid,  and  methyl-brom-cinna- 
mate. 

3.  The  chief  contribution  of  this  paper  to  the  science  of 
chemistry  may  be  briefly  stated,  then,  as  the  synthesis  of  cer- 
tain mono-amino-flavones,  all  of  which  possess  a  yellow  color, 
and  of  certain  flavone-azo-beta-naphthol  dyes  which  have 
deeper  colors  than  the  most  highly  hydroxylated  flavones  oc- 
curring in  nature.  Incidently,  4'-amino-flavone  has  been  found 
(as  far  as  the  solvents  which  were  tried  are  concerned)  to 
possess  the  unusual  property  of  causing  fluorescence  only  in 
neutral  solvents  which  contain  the  hydroxyl  group. 


THE  SYNTHESIS  OF  AMINO  FLAVONES,  OF 

FLAVONE-AZO-BETA-NAPHTHOL 

DYES,  AND  OF  OTHER  FLA- 

VONE  DERIVATIVES 


INTRODUCTORY 

Many  of  the  yellow  coloring  matters  occurring  in  thfe  plant 
kingdom  have  been  shown  to  be  hydroxy  derivatives  of  flavone 
(benz-2-phenyl-gamma-pyrone).*  Aside  from  the  general  in- 
terest attaching  to  these  compounds  because  of  their  ubiquitous 
occurrence  in  nature,  they  are  of  particular  importance  by 
reason  of  the  successful  commercial  application  of  some  of 
them  as  fast  dyes;  i.  e.,  Quercetin  (l,3,3',4',alpha-penta- 
hydroxy-flavone)  the  yellow  dyestuff  in  Quercitron  Bark,  and 
Morin  (1,3,2',4',  alpha-penta-hydroxy-flavone)  which,  together 
with  Maclurin  (a  penta-hydroxy-benzo-phenone),  constitutes 
the  coloring  matter  of  Old  Fustic. 

In  view  of  the  strong  chromophoric  character  of  the  benz- 
2-phenyl-gamma-pyrone  nucleus  displayed  in  these  compounds, 
it  was  considered  of  interest  to  extend  the  investigation  of 
the  flavone  series  to  the  preparation  and  study  of  the  amino 
derivatives,  in  order  to  record  the  auxochromic  effect  of  the  ami- 
no  group  on  the  flavone  nucleus,  and  to  couple  the  diazotized 
amines  with  beta-naphthol,  thus  incorporating  the  flavone,  azo 
and  naphthalene  chromophores  in  one  compound,  with  the  ex- 
pectation of  obtaining  red  or  blue  dyes — this  expectation  being 
warranted  by  the  numerous  examples  of  compounds  in  which 
a  deepening  in  color  is  brought  about  by  the  piling  up  of  chro- 
mophores. Further,  the  methods  which  have  been  elaborated 
for  the  preparation  of  flavone  involve  either  the  use  of  mate- 
rials which  are  difficult  to  obtain  in  quantity  or  the  employment 
of  a  long  succession  of  reactions  in  which  the  yields  at  some 
points  are  disappointing.6  Thus  it  seemed  desirable  to  devise 
a  new  method  for  making  compounds  of  this  series  which 
would  not  possess  the  disadvantages  above  named.  With  these 
objects  in  view,  the  investigation  reported  in  this  paper  was 
undertaken. 

The  work  was  successful  in  regard  to  (I)  the  preparation 
of  amino  flavones,  and  (II)  the  production  of  azo-flavone  dyes; 
but  was  not  fruitful  of  (III)  the  sought  for  better  method  for 
making  flavone  or  its  derivatives : — 

(I).  Three  mono-amino-flavones,  2'-amino-flavone,  3'- 
amino-flavone  and  4'-amino-flavone,  were  obtained  by  the  re- 

*  See  structure  I. 


duction  of  a  mixture  of  mono-nitro-derivatives  resulting  from 
the  nitration  of  flavone.  The  isomeric  nitro  compounds  were 
not  isolated  because  they  possessed  too  little  difference  of 
solubility  in  the  solvents  tried  to  give  a  satisfactory  separation. 
The  isolation  of  the  individual  amino-flavones,  however,  was 
effected  by  taking  advantage  of  their  differing  basicity  and 
solubilities. 

The  position  of  the  amino  group  in  each  one  of  the  three 
amino-flavones  which  were  synthesized  was  determined  by 
conversion  of  the  amine,  thru  its  diazonium  compound,  into 
the  corresponding  phenol. 

Two  of  the  phenols,  thus  obtained,  were  found  to  be 
identical  with  3'-hydroxy-flavone 5  and  4'-hydroxy-flavone,4 
which  were  both  previously  prepared  by  St.  v.  Kostanecki  by 
another  method.  The  third  phenol  proved  to  be  2'-hydroxy- 
flavone  which  has  been  hitherto  unknown. 

The  position  of  the  hydroxyl  group  in  2'-hydroxy-flavone 
was  determined  by  decomposing  it  with  sodium  ethoxide  * 7 
into  salicylic  acid  and  ortho-hydroxy-anisole. 

The  noteworthy  characteristics  of  the  amines  are : — 

1.  They  are  all  yellow;  the  2'-amine  being  pale  yellow; 
the  3'-amine,  lemon  yellow ;  and  the  4'-amine,  golden  yellow — 
thus  the  amino  group  seems  to  exert  a  stronger  auxochromic 
influence  than  the  hydroxyl  group  on  the  flavone  nucleus,  since 
2'-hydroxy-flavone,  3'-hydroxy-flavone,  and  4'-hydroxy-flavone 
are   all   white.     3'-Amino-flavone   and   4/-amino-flavone   were 
found  to  dye  wool  and  silk  directly  a  light  yellow  color. 

2.  The  4'-amino-flavone  stands  out  in  sharp  contrast  to 
the  other  two  amines,  especially  in  those  properties  relating 
to  color  effect;  i.  e.,  its  color  is  a  deeper  yellow  than  that  of 
the  other  amines ;  it  produces  an  intense  fluorescence  in  certain 
solvents   (the  unusual  nature  of  the  fluorescent  property  of 
this  amine  is  that  it  seems  to  be  manifested  only  in  solvents, 
which  contain  the  hydroxyl  group),  whereas  the  2'  and  3' 
isomers  show  no  fluorescence  in  any  solvent;  its  reduction 
with  magnesium  in  alcoholic  hydrochloric  acid  solution  pro- 
duces an  intensely  purple  colored  solution,  in  contrast  to  the 
light  orange  color  developed  in  each  case  by  similar  treatment 
of  the  other  two  amines ;  **  a  bright  red  dye  is  obtained  by 
coupling  the  diazotized  4'-amino-flavone  with  beta-naphthol, 
whereas  the  2'  and  3'  amines,  when  treated  in  the  same  way 
give  two  orange  dyes. 

Noteworthy,  also,  are  the  nitration  products  of  flavone — 
altho  the  individual  nitro  derivatives  were  not  isolated,  an 
ultimate  analysis  of  the  nitration  mixture  indicated  that  it  was 
composed  of  mono-nitro-flavones ;  and  this  was  corroborated 

*  See  equation  III. 

**  Anthocyan  formation  possibly  takes  place  in  this  reaction. 

10 


by  the  subsequent  isolation  of  three  mono-amines  (above) 
which  were  derived  from  the  nitro-flavone  mixture.  The  fol- 
lowing compounds,  then,  must  have  resulted  from  the  nitration 
of  flavone— 2'-nitro-flavone,  3/-nitro-flavone  and  ^-nitro-fla- 
vone. Thus,  all  the  possible  mono-nitro  products  arising  from 
substitution  in  the  phenyl  nucleus  of  flavone  have  been  formed, 
and  none  in  which  the  benz  ring  has  been  attacked.  This  may 
be  a  case  of  steric  hindrance;  and  it  would  be  of  interest  to 
learn  whether  further  nitration  of  mono-nitro-flavone  would 
be  limited  to  the  phenyl  nucleus. 

(II).  A  bright  red  dye  of  structure  (IV),*  fast  to  light 
and  alkalis,  was  obtained  by  coupling  the  diazotized  4'-amino- 
flavone  with  beta-naphthol ;  and  two  orange  dyes  of  structures 
(II)  *  and  (III),*  of  like  fastness,  resulted  by  the  similar 
coupling  of  each  of  the  diazotized  2'  and  3'  amino-flavones 
respectively. 

(III).  St.  v.  Kostanecki  showed  that  flavone  may  be 
conveniently  prepared  by  successive  treatments  of  flava- 
none  *  **  with  bromine  and  potassium  hydroxide.  But,  since 
the  formation  of  flavanone,  as  carried  out  by  the  same  investi- 
gator, involves  the  use  of  ortho-hydroxy-anisole  which  is  diffi- 
cult to  obtain  in  quantity,  the  following  attempt  was  made  to 
synthesize  it  from  cinnamic  acid  which  is  readily  available: — 

Beta-phenoxy-hydrocinnamic  acid  was  prepared  by  the 
action  of  phenol  on  beta-brom-hydrocinnamic  acid,  which  in 
turn  was  obtained  from  cinnamic  acid  and  hydrogen  bromide. 
The  hope  that  the  action  of  anhydrous  aluminum  chloride  on 
beta-phenoxy-hydrocinnamyl  chloride  would  effect  an  internal 
condensation  to  form  flavanone,  similar  to  the  condensation  of 
beta-phenoxy-cinnamyl  chloride  to  form  flavone,2  was  not 
realized.  An  attempt  was  also  made  to  accomplish  the  internal 
condensation  of  free  beta-phenoxy-hydrocinnamic  acid  t  by  the 
employment  of  concentrated  sulphuric  acid  as  a  dehydrating 
agent,  but  the  result  was  the  formation  of  a  disulfo-beta- 
phenoxy-hydrocinnamic  acid  instead.  Further  failure  to  effect 
condensation  of  the  free  acid  resulted  from  the  use  of  other 
dehydrating  agents  such  as  phosphorus  pentoxide,  anhydrous 
zinc  chloride  or  fuming  stannic  chloride. 

Because  of  the  well  known  influence  of  the  nitro  group 
in  a  benzene  ring  on  the  lability  of  the  hydrogen  atom  lying 
in  the  meta  position  to  it,  it  was  considered  probable  that 
flavanone  ring  formation  would  be  successful  with  beta-para- 
nitro-phenoxy-hydrocinnamic  acid.  With  the  purpose  of  ob- 
taining the  latter  substance,  para-nitro-phenol  was  heated  with 
beta-brom-hydrocinnamic  acid,  but  instead  of  the  expected 
acid,  a  compound  which  possesses  the  empirical  formula  for, 

*  See  structures. 
**  See  structure  V. 
t  See  equation  I. 

11 


and  is  believed  to  be,  2-nitro-flavanone  was  obtained.  The 
course  of  the  reaction  was  doubtless  a  preliminary  metathesis 
between  para-nitro-phenol  and  beta-brom-hydrocinnamic  to 
form  hydrogen  bromide  and  the  expected  acid  which  immedi- 
ately condensed  to  form  2-nitro-flavanone  with  the  elimination 
of  water.*  However,  in  view  of  the  small  yield  (2  per  cent 
of  the  calculated  amount)  of  the  nitro  flavanone  obtained,  the 
third  part  of  the  investigation  must  be  considered  successful 
only  in  so  far  that  one  flavanone  derivative  has  been  prepared 
in  poor  yield  by  a  new  rapid  method.  Not  enough  of  the 
compound  was  obtained  to  convert  to  the  nitro-flavone. 

The  procedure  adopted  in  this  paper  for  the  preparation 
of  flavone  is  a  modification  of  the  one  devised  by  Ruhemann.2 
It  was  found  that  the  interaction  of  ethyl-phenyl-propiolate 
with  sodium  phenolate  gave  not  one,  as  stated  by  Ruhemann, 
but  two  esters  which  on  saponification  yielded  two  isomeric 
acids,  one  of  which  corresponds  with  the  beta-phenoxy-cin- 
namic  acid  described  by  the  above  worker  and  the  other  of 
which  has  been  shown  to  be  either  beta-ortho-hydrpxy-phenyl- 
cinnamic  acid  or  beta-para-hydroxy-phenyl-cinnamic  acid. 

The  phenyl  propiolic  acid  used  in  the  flavone  synthesis 
was  prepared  by  a  modification  of  the  method  described  by 
Sudborough  and  Thompson.3 

The  other  compounds  which  were  prepared  for  the  pur- 
pose of  characterization  of  the  amino  flavones  or  hydroxy 
flavones  are :  2'-diacetyl  amino-flavone,  3'-diacetyl  amino- 
flavone,  4'-diacetyl  amino-flavone,  2'-acetoxy-flavone,  3'- 
acetoxy-flavone  and  4'-acetoxy-flavone. 


EXPERIMENTAL 
I  and  II. 

Beta-Phenoxy-C  i  n  n  a  m  i  c  Acid,  C6H5C(OC6H5)  :CH. 
COOH — Ruhemann  states  that  ethyl-beta-phenoxy-cinnamate 
may  be  prepared  by  adding  ethyl  phenyl  propiolate  to  a 
"warm"  mixture  of  sodium  phenolate  and  phenol.12  In  an 
attempt  to  duplicate  his  synthesis,  the  connotation  of  "warm" 
was  taken  to  be  about  60°-70° ;  but  in  carrying  out  the  re- 
action at  this  temperature,  only  part  of  the  sodium  phenolate 
dissolved  and  a  very  impure  product  which  distilled  over  a 
wide  range  (between  140°  and  215°  at  12  mm.),  and  smelled 
of  ethyl-phenyl-propiolate  was  obtained. 

It  was  found,  however,  that  when  ethyl-phenyl-propiolate 
was  added  to  sodium  phenolate  above  125°,  the  phenolate  dis- 
solved completely  and  the  reaction  was  accompanied  by  an 
evolution  of  heat. 

*See  equation  II. 

12 


Further,  it  was  found  desirable  to  use  a  xylene  solution 
of  phenol  in  preparing  sodium  phenolate — the  use  of  phenol 
alone  necessitates  a  very  slow  addition  of  the  sodium  since 
too  rapid  an  addition  causes  the  temperature  to  rise  to  the 
boiling  point  of  phenol  with  consequent  charring  of  some  of 
the  sodium  phenolate.  The  presence  of  xylene  confines  the 
rise  in  temperature  of  the  mixture  to  its  boiling  point  and 
therefore  the  sodium  may  be  added  more  rapidly. 

The  reaction  between  ethyl-phenyl-propiolate  *  and  sodi- 
um phenolate  suspended  in  xylene  and  an  excess  of  phenol  was 
carried  out  at  140°-150°.  The  reaction  product  was  treated 
according  to  the  directions  of  Ruhemann. 

After  the  excess  of  phenol,  xylene  and  ether  had  been 
removed,  the  product  gave  on  distillation  at  18  mm. : — 10  g.  of 
a  rather  viscous  colorless  liquid  from  203°  to  216°;  116.1  g. 
of  a  very  viscous  colorless  oil  from  216°  to  219°  (Ruhemann 
gives  the  B.P.  of  ethyl-beta-phenoxy-cinnamate  as  204°  to  205° 
at  10  mm.).  The  latter  fraction  solidified  (over  night)  to  a 
white  crystalline  mass.  M.P.  37°-45°  (Ruhemann  gives  the 
M.P.  of  ethyl-beta-phenoxy-cinnamate  as  73°-74°). 

The  116.1  g.  fraction  was  saponified  with  alcoholic  sodium 
hydroxide,  but,  contrary  to  the  finding  of  Ruhemann,  gave 
not  only  beta-phenoxy-cinnamic  acid  but  also  another  acid. 
They  were  separated  as  follows : — 

The  mixture  of  acids  was  dissolved  in  250  cc.  of  boiling 
alcohol.  On  cooling,  broad  prisms  came  down  at  first,  and 
later  fine  needles  began  to  appear.  At  this  point  the  warm 
liquid  was  poured  off  from  the  precipitate  of  prisms. 

The  decanted  solution  deposited  chiefly  the  needle  crys- 
tals, and  when  cool  was  filtered.  The  precipitate  was  re- 
crystallized  five  times  from  hot  ethyl  alcohol  and  the  result 
was  49  g.  of  a  fluffy  precipitate  of  fine  white  needles,  which 
softened  at  126°  and  melted  at  139°-140°  with  evolution  of 
gas.  This  product  was  fairly  pure  beta-phenoxy-cinnamic  acid 
and  was  used  in  the  preparation  of  flavone  (q.v.).  For  pur- 
poses of  comparison  with  the  acid  described  by  Ruhemann, 

*  The  ethyl-phenyl-propiolate  used  in  this  reaction  was  prepared  as 
described  by  Perkin10.  It  was  purified  by  distillation  in  vacuo. 

The  phenyl  propiolic  acid  was  prepared  by  a  modification  of  the 
method  of  Sudborough  and  Thompson3,  by  using  ethyl  di-brom-cinnamate 
instead  of  di-brom-cinnamic  acid,  because,  as  these  investigators  have 
shown,  a  much  greater  proportion  of  alpha-brom-cinnamic  acid  is  formed 
directly  from  the  ester  than  from  the  free  acid  in  the  first  treatment  with 
alcoholic  alkali11.  Also  the  alpha-brom-cinnamic  acid,  alpha-allo-brom- 
cinnamic  acid  and  phenyl  propiolic  acid  were  all  recrystallized  from  benzene 
instead  of  from  chloroform  and  petroleum  ether.  The  ethyl  di-brom- 
cinnamate  was  prepared  by  the  method  of  Perkin. 

Perkin's  method  for  preparing  phenyl  propiolic  acid  involves  fewer 
reactions  than  the  method  of  Sudborough  and  Thompson,  but  was  found 
to  give  a  poor  yield  (33%  of  the  amount  calculated  from  the  ethyl  dibrom- 
cinnamate). 

13 


some  of  the  above  product  was  further  recrystallized  (three 
times)  from  hot  alcohol  with  the  production  of  a  pure  sub- 
stance that  softened  at  127°  and  melted  at  143°-145°  (corr.) 
with  decomposition.  Ruhemann  gives  the  softening  point  as 
125°  and  melting  point  as  143°. 

Subs.  0.3213:  CO2,  0.8823;  H2O,  0.1503.    Calc.  for  CisHiaOs:  C,  75%: 
H,  5.0%.    Found :  C,  74.9% ;  H,  5.2%. 

The  compound  agrees  in  other  properties  with  the  acid 
described  by  Ruhemann. 

The  precipitate  of  broad  prisms  (8  grams)  was  recrystal- 
lized six  times  from  hot  ethyl  alcohol  and  1.7  g.  of  a  pure 
substance  softening  at  169°  and  melting  at  176°-177°  (corr.) 
was  obtained.  This  substance  is  not  mentioned  by  Ruhe- 
mann. 

Subs.  0.2110:  CO2,  0.5806;  H2O,  0.0968.  Calc.  for  Ci5Hi2O3:  C, 
75.0%;  H,  5.0%.  Found:  C,  75.1%;  H,  5.1%. 

The  analysis  shows  it  to  be  an  isomer  of  beta-phenoxy- 
cinnamic  acid.  From  its  properties  (q.v.)  it  is  believed  to 
be  either  beta-ortho-hydroxy-phenyl-cinnamic  acid  or  beta- 
para-hydroxy-phenyl-cinnamic  acid.  The  formation  of  either 
of  these  compounds  in  the  above  reaction  would  be  analogous 
to  the  formation  of  beta-para-hydroxy-phenyl-hydrocinnamic 
acid  from  phenol  and  allo-cinnamic  acid.13 

This  compound  gives  positive  tests  for  the  phenolic  hy- 
droxyl  group  with  Liebermann's  reagent  and  with  a  solution 
of  titanium  dioxide  in  concentrated  sulphuric  acid.  It  does 
not  give  a  coloration  in  water  or  alcohol  solution  with  ferric 
chloride. 

A  solution  of  the  substance  in  aqueous  sodium  carbonate 
reduces  potassium  permanganate  but  no  benzaldehyde  odor 
results,  thus  indicating  the  absence  of  the  C6H5CH :  group, 
which  shows  that  the  substance  is  not  alpha-hydroxyl-phenyl- 
cinnamic  acid.  It  is  not  alpha-phenoxy-cinnamic  acid,  since 
this  substance  melts  with  no  evolution  of  gas. 

The  two  remaining  possibilities  are  beta-ortho-hydroxy- 
phenyl-cinnamic  acid  or  beta-para-hydroxy-phenyl-cinnamic 
acid.  In  analogous  manner  to  the  behavior  of  coumarinic 
acid,  beta-ortho-hydroxy-phenyl  cinnamic  acid  should  yield, 
on  fusion,  a  coumarin  derivative.  The  compound  in  ques- 
tion, however,  decomposes  at  its  melting  point  with  evolution 
of  carbon  dioxide.  Therefore  this  method  of  fixing  the  posi- 
tion of  the  hydroxyl  group  could  not  be  used.  Lack  of  a 
sufficient  supply  of  the  substance  prevented  further  investi- 
gation to  decide  between  the  ortho  and  para  structures. 

The  compound  dissolves  in  concentrated  sulphuric  acid, 
forming  a  bright  yellow  solution.  It  decolorizes  a  chloroform 
solution  of  bromine.  Is  soluble  in  hot  ethyl  alcohol,  toluene 
or  ligroin  (100°-110°)  ;  insoluble  in  hot  water  or  carbon  disul- 
phide. 

14 


Flavone  (Benz-2-phenyl-gamma-pyrone) — was  prepared, 
with  few  modifications,  by  the  method  of  Ruhemann,2  in  which 
the  acid  chloride  of  beta-phenoxy-cinnamic  acid  is  treated  with 
anhydrous  aluminum  chloride.  It  was  found  that  the  quanti- 
ties of  benzene  and  aluminum  chloride,  indicated  by  Ruhe- 
mann, could  be  cut  down  without  affecting  the  yield  of  flavone  : 
— 320  g.  of  benzene  and  60  g.  of  anhydrous  aluminum  chloride 
were  used  for  30.5  g.  of  beta-phenoxy-cinnamic  acid.  The 
crude  flavone  was  recrystallized  from  ligroin  (100°-110°). 
The  yield  of  flavone  was  85%  on  the  calculated  amount. 

Nitration  of  Flavone — was  effected  by  the  action  of  nitric 
and  sulphuric  acids  on  a  solution  of  flavone  in  glacial  acetic 
acid.  It  was  found  necessary  to  dilute  the  sulphuric  acid  with 
glacial  acetic  acid,  since  the  use  of  the  former  acid  alone  gave 
rise  to  the  formation  of  higher  than  mono-nitro  derivatives. 
A  mixture  of  three  white  mono-nitro-flavones  was  obtained. 
All  attempts  to  limit  the  action  of  nitric  acid  on  flavone  to 
the  formation  of  only  one  nitro  flavone  derivative  failed. 

60.5  g.  of  flavone  were  dissolved  in  60  cc.  of  glacial  acetic 
acid,  and  180  cc.  sulphuric  acid  (1.84)  were  slowly  added 
thereto.  32  cc.  (3  cc.  more  than  the  theoretical  amount  re- 
quired for  the  formation  of  a  mono-nitro-flavone)  of  a  glacial 
acetic  acid  solution  of  nitric  acid  (1.5)  containing  0.58  g.  of 
nitric  acid  per  cc.  of  solution  were  slowly  added,  while  cooling, 
to  the  above  flavone  mixture.  After  standing  at  the  ice-box 
temperature  for  three  days,  the  solution  was  poured  into  ice  and 
water.  The  faint  yellow  colored  precipitate  that  came  down 
was  filtered,  well  washed  with  water,  and  dried  over  sulphuric 
acid  in  vacuo.  The  69  g.  of  nitro  flavone  thus  obtained 
were  dissolved  in  350  cc.  of  boiling  glacial  acetic  acid  and  on 
cooling,  the  pale  yellow  solution  deposited  39  g.  of  a  white 
crystalline  product,  which  when  dry,  melted  from  174°  to 
205°.  Some  of  this  product  was  prepared  for  analysis  by  an- 
other crystallization  from  glacial  acetic  acid.  M.P.  175°-206°. 

Subs.  0.3112:  CChz,  0.7677;  H2O,  0.0871.  Calc.  for  Ci*HaO4N:  C, 
67.4% ;  H,  3.3%.  Found  :  C,  67.3% ;  H,  3.2%. 

Subs.  0.2813:  13.6  cc.  nitrogen  at  23°,  752  mm.  Calc.  for  CwHgOfcN: 
N,  5.2%.  Found :  N,  5.4%. 

The  analysis  together  with  the  wide  range  of  melting 
point  indicates  that  the  material  was  composed  of  a  mixture 
of  mono-nitro-flavones,  and  its  subsequent  conversion  (q.v.) 
into  3'-amino-flavone  and  4'-amino-flavone  proved  that  it  con- 
sisted of  3'-nitro-flavone  and  4'-nitro-flavone. 

This  mono-nitro-flavone  mixture  is  slightly  soluble  in  hot 
ether,  ligroin  (100°-110°)  or  carbon  tetrachloride ;  insoluble  in 
hot  carbon  disulfide  or  petroleum  ether ;  moderately  soluble  in 
hot  glacial  acetic  acid,  acetic  anhydride,  acetone,  ethyl  alcohol, 
methyl  alcohol,  benzene,  chloroform,  nitro-benzene,  toluene, 

15 


xylene,  ethyl  acetate,  amyl  alcohol  (technical)  or  amyl  acetate ; 
very  soluble  in  cold  aniline  and  fairly  so  in  cold  pyridine. 

It  is  soluble  in  cold  concentrated  sulphuric  acid  or  con- 
centrated hydrochloric  acid.  It  is  insoluble  in  cold  or  boiling 
aqueous  sodium  hydroxide,  concentrated  or  dilute. 

To  the  hot  glacial  acetic  acid  filtrate  from  the  above  3'  and 
4'  nitro  flavones  were  added  200  cc.  of  hot  water,  and  on 
standing  over  night,  19  g.  of  a  white  crystalline  product  came 
down  which,  when  dry,  melted  at  143°  to  168°.  Some  of  this 
product  was  prepared  for  analysis  by  another  crystallization 
from  glacial  acetic  acid.  M.P.  148°-170°. 

Subs.  0.3121:  C02,  0.7709;  H2O,  0.0976.  Calc.  for  CisHgO^N:  C, 
67.4% ;  H,  3.3%.  Found :  C,  67.4% ;  H,  3.5%. 

Subs.  0.2464:  Nitrogen  11.7  cc.  at  25°,  759  mm.  Calc.  for  Ci5H9O4N: 
N,  5.2%.  Found:  N,  5.3%. 

The  conversion  of  this  product  into  2'-amino-flavone  and 
3'-amino-flavone  (q.v.),  together  with  its  analysis,  proved  that 
it  was  composed  of  a  mixture  of  2'-nitro-flavone  and  3'-nitro- 
flavone.  No  4'-nitro-flavone  was  present  in  this  product  as 
was  indirectly  proved  by  the  absence  of  fluorescence  in  an  amyl 
alcohol  or  other  solution  of  the  amine  mixture  derived  there- 
from— the  presence  of  4'-amino-flavone  would  have  caused  an 
intense  blue  or  green  fluorescence. 

Solubilities,  similar  to  those  of  the  mixture  of  3'  and  4' 
nitro-flavones,  are  possessed  by  this  product. 

2/-Amino-flavone — was  obtained  by  reduction,  with  stan- 
nous  chloride,  of  the  mixture  of  2'  and  3'  nitro-flavones,  and 
subsequent  separation  of  the  two  amines  thus  formed  by  means 
of  the  difference  in  solubility  in  water  of  their  hydrochlorides. 

19  g.  of  the  mixture  of  2'  and  3'  nitro-flavones  were  sus- 
pended in  250  cc.  of  boiling  alcohol  and  134  cc.  of  stannous 
chloride  solution  containing  24  g.  of  tin  and  40  g.  of  hydrogen 
chloride  (theory  requires  24  g.  of  tin  and  14  g.  of  hydrogen 
chloride)  were  added.  In  two  minutes  all  had  dissolved  to  a 
clear  orange  solution.  Added  5  cc.  more  of  the  stannous 
chloride  solution  and  boiled  for  ten  minutes.  On  cooling, 
orange  colored  microscopic  crystals  came  down.  Allowed  the 
mixture  to  stand  in  the  ice  box  over  night.  Filtered.  Dried 
in  the  air.  The  orange  powder  (34  g.)  was  added  to  two  liters 
o^hot  water  and  most  of  it  dissolved  leaving  a  gelatinous  white 
precipitate  (tin  hydroxides)  in  suspension.  The  mixture  was 
saturated  with  hydrogen  sulfide,  and  the  tin  sulfides  were  re- 
moved by  filtration.  The  yellow  filtrate  was  made  alkaline 
with  dilute  sodium  carbonate,  whereupon  a  yellow  precipitate 
was  formed.  This  was  filtered,  washed  with  water  and  dried 
over  sulphuric  acid.  Yield=13  g.  This  product  gave  no  flu- 
orescence in  amyl  alcohol  or  other  solution  which  showed  that 
4'-amino-flavone  was  absent. 

16 


V 

The  13  g.  of  yellow  substance  was  then  suspended  in  150 
cc.  of  5%  hydrochloric  acid  and  the  mixture  boiled  and  stirred 
for  five  minutes,  whereupon  some  of  the  solid  went  into  solu- 
tion. 5  cc.  of  concentrated  hydrochloric  acid  were  added,  the 
boiling  continued  for  five  minutes  and  as  soon  as  the  mixture 
had  cooled  to  room  temperature,  it  was  filtered.  The  precipi- 
tate consisted  of  the  hydrochlorides  of  2'-amino-flavone  mixed 
with  a  little  3'-amino-flavone.  The  filtrate  contained  3'-amino- 
flavone  mixed  with  a  considerable  amount  of  2'-amino-flavone. 

The  precipitate  was  suspended  in  an  excess  of  dilute 
sodium  carbonate  solution,  heated  on  the  water  bath  and  stirred 
for  fifteen  minutes  until  the  hydrochloride  was  completely 
converted  to  the  free  amine,  which  was  filtered,  washed,  and 
dried  over  sulphuric  acid.  Yields?  g.  Two  crystallizations 
from  hot  acetone  gave  thin  pale  yellow  silky  needles.  Melted 
at  149.5°-150.5°  (corr.)  to  a  yellow  liquid. 


Subs.  0.2132:   CO2,  0.5931;  H2O,  0.0901.    Calc.   for   OikHnOftN:   C, 
75.9%  ;  H,  4.6%.    Found  :  C,  75.9%  ;  H,  4.7%. 

Subs.  0.2512:  N,  13.1  cc.  at  19°,  765  mm.    Calc.  for  CisHiiO2N:  N, 
5.9%.    Found  :  N,  6.0%. 

Subsequent  conversion  of  this  amine,  by  decomposition 
with  water  of  its  diazonium  salt,  into  the  corresponding  phenol 
which,  in  turn  was  converted  into  salicylic  acid  and  ortho- 
hydroxy-anisole,  proved  that  the  amino  group  occupied  the  2' 
position  in  the  flavone  nucleus. 

The  substance  gives  a  positive  isonitrile  test  showing  it 
to  be  a  primary  amine.  It  is  slightly  soluble  in  hot  concen- 
trated hydrochloric  acid  and  moderately  so  in  the  same  hot 
dilute  acid,  from  which  on  cooling,  fine  white  silky  needles 
precipitate.  It  is  soluble  in  cold  concentrated  sulphuric  acid, 
forming  a  colorless  solution.  From  its  solution  in  hot  20% 
sulphuric  acid,  on  cooling,  colorless  straight  thick  bars  come 
down.  Dissolves  in  concentrated  nitric  acid,  forming  a  yellow 
solution.  It  reduces  a  solution  of  potassium  permanganate 
and  dilute  sulphuric  acid  in  the  cold.  In  warm  dilute  sul- 
phuric solution  it  gives  a  black  amorphous  precipitate  with 
potassium  dichromate. 

The  amine  is  easily  soluble  in  cold  aniline,  or  in  hot  py- 
ridine,  ethyl  alcohol,  methyl  alcohol,  acetone,  glacial  acetic 
acid,  chloroform,  benzene,  toluene,  xylene,  ethyl  acetate,  amyl 
alcohol,  amyl  acetate  or  nitro-benzene.  It  is  moderately  sol- 
uble in  hot  ligroin  (100°-110°),  slightly  soluble  in  hot  ether, 
carbon  disulfide,  or  carbon  tetrachloride,  insoluble  in  hot  water 
or  petroleum  ether. 

4'-Amino-flavone  —  was  obtained  by  reduction  with  stan- 
nous  chloride,  of  the  mixture  of  3'  and  4'  nitro-flavones  (above) 
and  subsequent  separation  of  the  resulting  amines  by  heating 
their  hydrochlorides  with  water,  which  effected  the  solution 

17 


of  the  3'-amine-hydrochloride  and  the  precipitation  of  the  free 
4'-amine. 

35  g.  of  the  3'  and  4'  nitro-flavones  were  suspended  in 
800  cc.  of  boiling  ethyl  alcohol  and  246  cc.  of  stannous  chloride 
solution  containing  42  g.  of  tin  and  72  g.  of  hydrogen  chloride 
(theory  requires  44  g.  of  tin  and  25  g.  of  hydrogen  chloride) 
were  added.  In  five  minutes  all  had  dissolved  to  a  dark  orange 
solution.  Added  10  cc.  more  of  the  stannous  chloride  mixture 
and  after  boiling  further  for  two  minutes  a  heavy  precipitate 
of  orange  colored  microscopic  crystals  separated.  Let  stand 
in  the  ice  box  over  night.  Filtered.  Divided  the  precipitate 
(for  convenience  of  manipulation  of  the  large  volumes  of  water 
used  later)  into  three  parts,  and  boiled  each  part  with  three 
and  one-half  liters  of  water  for  fifteen  minutes.  Most  of  the 
precipitate  went  into  solution  leaving  a  mixture  of  a  yellow 
flocculent  solid  and  a  white  gelatinous  mass.  Filtered  when 
cool. 

The  filtrates  were  saturated  with  hydrogen  sulphide  and 
the  small  amount  of  tin  sulphide  that  came  down  was  filtered 
off.  The  filtrates  were  made  alkaline  with  dilute  sodium  car- 
bonate and  a  precipitate  of  small  yellow  needles  deposited. 
The  combined  dry  precipitates  weighed  12  g.  and  consisted 
mainly  of  3'-amino-flavone  mixed  with  a  small  amount  of  4'- 
amino-flavone. 

The  combined  precipitates  (the  filtrates  from  which  de- 
posited 3'-amino-flavone)  were  heated  with  100  cc.  of  10% 
hydrochloric  acid,  whereupon  the  yellow  substance  dissolved 
leaving  a  white  mass  (stannic  oxide)  which  was  removed  by 
filtration.  The  filtrate  was  made  alkaline  with  dilute  sodium 
carbonate — the  yellow  precipitate  that  came  down  was  filtered, 
washed,  and  dried  over  sulphuric  acid.  Yield=7  g. 

The  small  amount  of  tin  oxide  present  in  this  product  was 
removed  by  treating  it  with  hot  pyridine  in  which  the  amine 
dissolved  leaving  a  small  amount  of  a  dark  residue  which  was 
removed  by  filtration.  The  pyridine  filtrate,  on  cooling,  de- 
posited the  amine,  which,  after  one  more  crystallization  from 
the  same  solvent  and  then  another  crystallization  from  boiling 
xylene,  was  obtained  in  the  form  of  extremely  long  (3  cm.) 
golden  yellow  needles,  which  melted  at  234°-236°  (corr.)  to  a 
yellow  brown  liquid. 

Subs.  0.2152;  CO*},  0.5979;  H'2O,  0.0852.    Calc.  for  CifcHnlW:   C, 
75.9% ;  H,  4.6%.    Found :  C,  75.8% ;  H,  4.4%. 

Subs.  0.3501:  N,  17.7  cc.  at  18°,  761  mm.    Calc.  for  CisH-nOsN:  N, 
5.9%.    Found :  N,  6.0%. 

The  position  of  the  amino  group  of  this  compound  was 
determined  similarly  as  in  the  case  of  2'-amino-flavone. 

The  compound  gives  a  positive  isonitrile  test,  showing 
that  it  is  a  primary  amine.  It  is  slightly  soluble  in  hot  con- 
centrated hydrochloric  acid  and  moderately  so  in  the  same 

18 


dilute  acid,  from  which,  on  cooling,  small  white  needles  de- 
posit. It  is  soluble  in  cold  concentrated  sulphuric  acid  (form- 
ing a  colorless  liquid).  Orange  needles  deposit  from  its  solu- 
tion in  hot  20%  sulphuric  acid  on  cooling.  A  deep  perman- 
ganate-purple solution  results  on  warming  the  amine  in  alco- 
holic hydrochloric  acid  with  magnesium.  It  reacts  similarly 
to  2'-amino-flavone  (q.v.)  with  potassium  permanganate,  po- 
tassium dichromate  or  concentrated  nitric  acid  solutions.  It 
is  easily  soluble  in  hot  aniline,  pyridine,  nitro-benzene,  or 
glacial  acetic  acid.  It  is  moderately  soluble  in  hot  acetone, 
ethyl  alcohol,  methyl  alcohol,  chloroform,  benzene,  toluene, 
xylene,  ethyl  acetate,  iso-amyl  alcohol  or  amyl  acetate.  It  is 
slightly  soluble  in  hot  ligroin  (100°-110°),  ether,  carbon  tetra- 
chloride  or  glycerol.  It  is  insoluble  in  hot  water,  carbon  disul- 
phide  or  petroleum  ether. 

4'-amino-flavone  was  found  to  impart  an  intense  bluish- 
green  fluorescence  to  iso-amyl  alcohol,  glycerol  or  ethyl  alco- 
hol ;  an  intense  blue  fluorescence  to  ether,  acetone,  ethyl  ace- 
tate, amyl  acetate  or  pyridine;  a  faint  green  fluorescence  to 
methyl  alcohol  or  phenol.  No  fluorescence  was  observed  in 
solutions  of  the  amine  in  chloroform,  benzene,  toluene,  xylene, 
ligroin,  carbon  tetrachloride  or  glacial  acetic  acid. 

An  inspection  of  the  above  solvents  (excluding  pyridine) 
shows  that  those  which  give  rise  to  the  fluorescence  contain 
the  alcohol  hydroxyl  group  (the  ethyl  acetate,  amyl  acetate, 
ether  and  acetone  used,  were  of  the  ordinary  "C.  P."  quality 
and  so  all  contained  impurities  of  alcohol;  i.  e.,  ethyl  alcohol 
in  ethyl  acetate  and  in  ether ;  amyl  alcohol  in  amyl  acetate ; 
and  methyl  alcohol  in  acetone).  Unlike  these  solvents,  ligroin, 
benzene,  toluene,  xylene,  chloroform,  glacial  acetic  acid  or 
carbon  tetrachloride  contain  no  impurities  of  an  alcoholic 
nature. 

In  order  to  more  definitely  confirm  the  relationship  be- 
tween the  presence  of  the  alcohol  group  and  the  production 
of  fluorescence  with  4'-amino-flavone,  some  of  the  amine  was 
dissolved  in  specially  prepared  pure  ether  *  (alcohol  and  water 
free),  with  the  surprising  result  that  no  trace  of  fluorescence 
was  apparent.  However,  when  a  drop  of  ethyl  alcohol  was 
added  to  this  ether  solution  an  intense  blue  fluorescence  im- 
mediately appeared. 

Likewise,  when  a  drop  of  water  was  added  to  a  solution 
of  the  amine  in  the  pure  ether,  an  intense  blue  fluorescence 
appeared — this  makes  it  seem  that  the  hydroxyl  group  of  water 
as  well  as  that  from  an  alcohol  will  cause  the  fluorescence. 

The  failure  of  solvents  like  ligroin,  benzene,  etc.,  to  pro- 
duce fluorescence  with  the  amine  seems  anomalous  at  first, 

*  The  author  is  indebted  to  Prof.  J.  M.  Nelson,  from  whom  this  ether 
was  obtained.  It  was  used  by  Prof.  Nelson  in  his  work  on  "Electro- 
motive Force  in  Non-Aqueous  Solvents."14 

19 


in  view  of  the  fact  that  these  solvents  contain  some  water. 
But  the  following  experiment  seems  to  show  that  a  rather  high 
concentration  of  hydroxyl  radical  is  necessary  to  produce  the 
fluorescence : — to  5  cc.  of  hot  benzene  was  added  an  excess  of 
4'-amino-flavone.  To  this  hot  mixture  was  added,  drop  by 
drop,  iso-amyl-alcohol ;  when  a  drop  of  the  alcohol  came  in 
contact  with  the  surface  of  the  benzene  solution,  an  intense 
blue  fluorescence  was  formed  at  that  place,  but  on  shaking  the 
mixture  the  fluorescence  disappeared.  It  was  only  when  0.5 
cc.  of  the  alcohol  had  been  added  that  the  fluorescence  became 
permanent.  The  failure,  then,  of  solvents  like  ligroin,  benzene, 
etc.,  to  produce  fluorescence  with  the  amine,  may  be  due  to 
their  not  containing  enough  water. 

No  fluorescence  is  observed  with  the  4'  amino-flavone  in 
water,  presumably  because  the  amine  is  insoluble  in  water, 
cold  or  hot.  The  amine  does  not  fluoresce  in  glacial  acetic 
acid,  or  in  glacial  acetic  acid  to  which  has  been  added  water 
(not  enough  to  cause  the  amine  to  precipitate) — most  likely 
because  of  the  action  of  the  acetic  acid  in  neutralizing  the 
amino  group,  the  presence  of  which  in  the  free  condition,  only, 
causes  the  fluorescence.  The  presence  of  fluorescence  in  a 
pyridine  solution  of  the  amine  is  doubtless  due  to  the  water 
present  in  this  solvent. 

Another  peculiar  property  of  this  amine  is  that  it  dissolves 
in  some  solvents  with  the  formation  of  yellow  solutions  and 
in  others  forming  colorless  solutions : — yellow  in  ethyl  alcohol, 
methyl  alcohol,  ethyl  acetate  or  glacial  acetic  acid ;  colorless 
in  benzene,  toluene,  xylene,  ligroin  (100°-110°)  chloroform, 
carbon  tetrachloride,  iso-amyl  alcohol  or  amyl  acetate. 

Light  yellow  colors  on  wool  and  silk  were  obtained  by 
impregnating  these  fibres  with  a  hot  solution  of  the  4'-amino- 
flavone  hydrochloride  in  the  presence  of  an  excess  of  hydro- 
chloric acid,  and  then  developing  the  color  in  dilute  sodium 
carbonate  solution. 

3 '-Amino-flavone — was  obtained  pure  by  recrystallization, 
from  pyridine,  of  the  yellow  product  that  was  precipitated  by 
neutralization  of  the  filtrate  from  the  precipitate  of  4'-amino- 
flavone  (above). 

12  g.  of  the  crude  amine  (M.P.  144°-149.5°)  were  recrys- 
tallized  twice  from  pyridine  and  then  once  from  xylene — lemon- 
yellow  straight  needles  were  obtained.  Melted  156°-157° 
(corr.)  to  a  yellow  liquid.  Yield=8  g. 

Subs.  0.2410:   CO2,  0.7068;   H2O,  0.0997.     Calc.   for  CifeH'nOaN:   C, 
79.9% ;  H,  4.6%.    Found :  C,  80.0% ;  H,  4.6%. 

Subs.  0.3101:  N,  16.8  cc.  at  20°,  749  mm.    Calc.  for  Ci5HiiO2N:  N, 
5.9%.    Found:  N,  6.1%. 

The  position  of  the  amino  group  of  this  compound  was 
determined  similarly  as  with  2'-amino-flavone. 

20 


The  compound  gives  a  positive  isonitrile  test,  thus  show- 
ing it  to  be  a  primary  amine.  It  is  somewhat  soluble  in  con- 
centrated hydrochloric  acid  and  easily  so  in  hot  dilute  hydro- 
chloric acid  from  which,  on  cooling,  it  precipitates  as  fine 
white  silky  needles. 

It  is  soluble  in  concentrated  sulphuric  acid  (forming  a 
colorless  solution)  ;  its  solution  in  hot  dilute  sulphuric  acid 
(20%),  on  cooling,  deposits  white  needles.  It  reacts  similarly 
to  2'-amino-flavone  (q.v.)  with  potassium  permanganate,  po- 
tassium dichromate  or  concentrated  nitric  acid  solutions. 

It  is  easily  soluble  in  cold  aniline  or  acetone ;  in  hot  glacial 
acetic  acid  or  nitro-benzene.  Is  moderately  soluble  in  hot 
ethyl  alcohol,  chloroform,  benzene,  toluene,  xylene,  ethyl  ace- 
tate, amyl  alcohol  or  amyl  acetate.  Is  slightly  soluble  in  hot 
ligroin  (100°-110°),  ether,  carbon  disulfide  or  carbon  tetra- 
chloride.  Is  insoluble  in  hot  water,  or  petroleum  ether. 

Light  yellow  colors  were  obtained  from  this  amine  on 
wool  and  silk,  by  using  a  similar  procedure  to  that  outlined 
above  for  4'-ammo-flavone. 

2'-Diacetyl-amino-flavone — 1  g.  of  2'-amino-flavone  was 
added  to  10  cc.  of  acetic  anhydride.  In  one  minute  the  yellow 
amine  was  converted  to  a  white  solid,  which  dissolved  on 
the  application  of  heat.  The  solution  was  boiled  for  five  hours. 
At  the  end  of  this  time,  most  of  the  acetic  anhydride  was 
evaporated  at  the  boiling  point,  and  the  rest  at  room  tem- 
perature with  a  current  of  air.  The  solid  that  remained  was 
recrystallized  twice  from  ethyl  alcohol.  Small  shining  white 
oblong  prisms  were  obtained.  M.P.  186.5°-187.5°  (corr.). 
Yield:=0.9  g. 

Subs.  0.2411:  N,  9.5  cc.  at  18°,  756  mm.  Calc.  for  CwHisOiN:  N, 
4.4%.  Found :  N,  4.5%. 

The  compound  is  readily  soluble  in  hot  acetone,  chloro- 
form, glacial  acetic  acid  or  acetic  anhydride.  Is  moderately 
soluble  in  hot  ethyl  alcohol  or  benzene.  Is  slightly  soluble  in 
hot  ether,  and  insoluble  in  hot  petroleum  ether,  carbon  disul- 
fide, carbon  tetrachloride  or  ligroin  (100°-110°).  Dissolves  in 
concentrated  sulphuric  acid,  forming  a  colorless  solution. 

3'-Diacetyl-amino-flavone. — 1  g.  of  3'-amino-flavone  was 
carried  through  a  similar  treatment  with  acetic  anhydride  (as 
above).  The  solid  that  remained  after  evaporation  of  the 
acetic  anhydride  was  recrystallized  thrice  from  hot  acetone. 
Delicate  small  hair-like  white  needles  were  obtained.  M.P. 
231°-232°  (corr.).  Yield=0.8  g. 

Subs.  0.2612:  N,  10.3  cc.  at  17°,  768  mm.  Calc.  for  C^Hi5O4N:  N, 
4.4%.  Found:  N,  4.6%. 

The  compound  is  easily  soluble  in  hot  ethyl  alcohol  or 
glacial  acetic  acid.  Is  moderately  soluble  in  hot  benzene, 

21 


toluene,  or  ethyl  acetate.     Dissolves  in  cold  concentrated  sul- 
phuric acid,  forming  a  colorless  solution. 

4'-Diacetyl-amino-flavone.  —  1  g.  of  4'-amino-flavone  was 
treated  with  acetic  anhydride,  as  above.  The  solid  residue, 
remaining  from  the  evaporation  of  the  acetic  anhydride,  was 
crystallized  once  from  dilute  ethyl  alcohol,  and  balls  of  micro- 
scopic crystals  came  down  which,  when  dried,  melted  175°- 
222°,  thus  showing  the  product  to  be  a  mixture.  This  product 
was  dissolved  in  10  cc.  of  acetic  anhydride  and  the  solution 
boiled  again  for  five  hours.  The  acetic  anhydride  was  re- 
moved by  evaporation,  and  the  solid  residue  was  recrystallized 
thrice  from  dilute  ethyl  alcohol.  Small  hair-like  white  needles 
were  obtained.  M.P.  246°-248°  (corr.).  Yield=0.65  g. 


Subs.  0.2112:  N,  8.4  cc.  at  15°,  751  mm.  Calc.  for  CifcHisCUN:  N, 
4.4%.  Found  :  N.  4.6%. 

The  compound  is  readily  soluble  in  cold  ethyl  alcohol  or 
glacial  acetic  acid.  Is  moderately  soluble  in  hot  benzene, 
toluene,  xylene  or  ethyl  acetate.  Dissolves  in  cold  concen- 
trated sulphuric  acid,  forming  a  colorless  solution. 

2'-Hydroxy-flavone  —  was  synthesized  by  the  decomposi- 
tion, in  water  solution,  of  the  diazonium  salt  derived  from 
2'-amino-flavone,  and  is  the  sixth  of  the  eight  possible  mono- 
hydroxy-flavones  to  be  isolated,  the  other  five  having  first  * 
a  different  method  than  that  used  by  Kostanecki. 
been  synthesized  by  Kostanecki.8 

3.5  g.  of  2'-amino-flavone  were  heated  with  20  cc.  of  con- 
centrated hydrochloric  acid  in  150  cc.  of  water.  To  the  mix- 
ture at  5°  were  added  8.4  cc.  of  sodium  nitrite  solution  con- 
taining 1  g.  of  sodium  nitrite  (calculated  amount).  After 
stirring  for  one-half  hour  the  amine  hydrochloride  had  entirely 
dissolved.  Boiled  the  solution  for  ten  minutes  (the  diazo  salt 
decomposes  slowly  below  the  boiling  point).  At  the  end 
of  this  time  nitrogen  ceased  to  be  evolved.  Cooled,  and  filtered 
the  slightly  colored  flocculent  precipitate.  Washed  with  water. 
On  stirring  in  200  cc.  of  1%  aqueous  sodium  hydroxide,  the 
precipitate  dissolved,  leaving  a  small  amount  of  a  brown  solid 
which  was  removed  by  filtration.  The  yellow  filtrate  on  acidifi- 
cation with  dilute  hydrochloric  acid,  gave  a  white  flocculent 
precipitate.  This  was  washed  with  water,  and  recrystallized 
thrice  from  alcohol.  Shining  white  plates  were  obtained. 
M.P.  249°-250°  (corr.).  Yield=2.2  g. 

Subs.  0.2101:  C02,  0.5828;  H«A  0.0816.  Calc.  for  C^H^O*:  C, 
75.6%  ;  H,  4.2%.  Found  :  C,  75.7%  ;  H,  4.3%. 

Subsequent  conversion  of  this  hydroxy-flavone  into  salicy- 
lic acid  and  ortho-hydroxy-anisole  (q.v.),  proved  the  hydroxyl 
group  to  occupy  the  2'  position  in  the  flavone  nucleus. 

*Two  of  these  five  have  been  also  synthesized  in  this  work  (q.  v.)  by 

22 


The  compound  dissolves  slowly  in  cold  concentrated  sul- 
phuric acid  forming  a  greenish  yellow  solution  with  a  slight 
green  fluorescence.  It  is  soluble  in  cold  dilute  or  hot  con- 
centrated aqueous  sodium  hydroxide — from  the  latter  solution, 
on  cooling,  small  yellow  needles  are  deposited. 

It  is  readily  soluble  in  hot  glacial  acetic  acid.  Is  mod- 
erately soluble  in  hot  acetone,  chloroform,  ethyl  acetate,  amyl 
acetate,  ethyl  alcohol,  xylene  or  toluene.  Is  slightly  'soluble 
in  hot  ether  or  benzene. 

3'-Hydroxy-flavone  * — was  prepared  in  similar  manner  to 
2'-hydroxy-flavone  (in  the  previous  experiment).  The  crude 
hydroxy-flavone  was  recrystallized  twice  from  ethyl  alcohol. 
From  4  g.  of  3'-amino-flavone  were  obtained  2.5  g.  of  shining 
white  narrow  plates.  M.P.  207°-208°  (corr.).  St.  v.  Kostan- 
ecki  gives  208°. 

Subs.   0.1762:    CO2,   0.4894;    H2O,   0.0650.    Calc.    for    Ci5Hi0O3:    C, 
75.6%;  H,  4.2%.    Found:  C,  75.8%;  H,  4.1%. 

Subsequent  conversion  of  this  hydroxy-flavone  (q.v.)  to 
meta-hydroxy-benzoic  acid  and  ortho-hydroxy-anisole,  con- 
firmed the  position  of  the  hydroxyl  group  in  the  flavone  nu- 
cleus as  assigned  to  it  above. 

The  compound  is  soluble  in  cold  dilute  or  hot  concentrated 
aqueous  sodium  hydroxide — from  the  latter  solution,  on  cool- 
ing, yellow  needles  are  deposited. 

4'-Hydroxy-flavone  * — was  prepared  in  similar  manner  to 
2'  and  3'-hydroxy-flavones  (above).  The  crude  hydroxy- 
flavone  was  recrystallized  thrice  from  a  mixture  of  pyridine 
and  alcohol.  Small  white  needles  were  obtained.  M.P.  269°- 
270°  (corr.).  St.  v.  Kostanecki  gives  M.P.  268°.  Yield=2.1 
g.  from  4  g.  of  4'-amino-flavone. 

Subs.  0.1523:  CO2,  0.4212;  H,  0.0594.    Calc.  for  C^HioOs:  C,  75.6%; 
H,  4.2%.    Found:  C,  75.5%;  H,  4.4%. 

The  compound  dissolves  in  cold  concentrated  sulphuric 
acid,  forming  a  yellow  solution  with  a  green  fluorescence 
which,  on  long  standing  of  the  solution,  changes  to  a  bluish 
fluorescence. 

Subsequent  conversion  of  this  hydroxy-flavone  into  para- 
hydroxy-benzoic  acid  and  ortho-hydroxy-anisole  (q.v.)  con- 
firmed the  position  of  the  hydroxyl  group  on  the  flavone  nu- 
cleus as  assigned  to  it  above. 

2'-Acetoxy-flavone. — 0.5  g.  of  2'-hydroxy-flavone,  1  g.  of 
anhydrous  sodium  acetate,  and  5  cc.  of  acetic  anhydride  were 
heated  to  boiling  for  one-half  hour.  5  cc.  of  water  were  added, 
and  the  mixture  was  warmed  on  the  water  bath,  to  hydrolyze 
the  excess  of  acetic  anhydride.  10  cc.  more  of  water  were 
added  to  dissolve  the  sodium  acetate — the  oil,  which  had  sepa- 

*  These  hydroxy-flavones  were  first  synthesized  by  St.  v.  Kostanecki  by 
another  method  than  the  one  used  here8. 

23 


rated,  after  remaining  in  the  ice-box  over  night,  changed  to 
a  crystalline  solid.  Filtered,  washed  with  water,  and  recrys- 
tallized  twice  from  dilute  alcohol.  Long  thin  white  needles 
were  obtained.  M.P.  88.5°-89°  (corn).  Yield=0.4  g. 

Subs.  0.2131:  CO2,  0.5703;  H2O,  0.0838.  Calc.  for  Ci7Hi2O4:  C, 
72.9%;  H,  4.3%.  Found:  C,  73.0%;  H,  4.4%. 

The  compound  is  soluble  in  cold  glacial  acetic  acid,  ethyl 
acetate,  benzene  or  acetic  anhydride.  Is  somewhat  soluble  in 
hot  ligroin  (100°-110°). 

3'-Acetoxy-flavone — was  prepared  as  directed  by  St.  v. 
Kostanecki,  by  heating  3'-hydroxy-flavone  with  acetic  anhy- 
dride and  anhydrous  sodium  acetate.5  Long  colorless  needles 
were  obtained  by  two  crystallizations  from  dilute  alcohol. 
M.P.  97°-98°  (corr.).  St.  v.  Kostanecki  gives  97°.  0.5  g.  of 
the  phenol  gave  0.3  g.  of  the  acetyl  derivative. 

Subs.  0.1857:  CO2,  0.4956;  H2O,  0.0747.  Calc.  for  Ci7HioO4:  C, 
72.9%;  H,  4.3%.  Found:  C,  72.8%;  H,  4.5%. 

4'-Acetoxy-flavone — was  obtained  from  4'-hydroxy-flavone 
with  acetic  anhydride  and  sodium  acetate  as  directed  by  St.  v. 
Kostanecki.4  White  needles  were  obtained  by  two  recrys- 
tallizations  from  dilute  alcohol.  M.P.  136°  (corr.).  St.  v. 
Kostanecki  gives  137°.  0.5  g.  of  the  phenol  gave  0.35  g.  of 
the  acetyl  derivative. 

Subs.  0.1023:  CO2,  0.2738;  H2O,  0.0411.  Calc.  for  diK^O*:  C, 
72.9% ;  H,  4.3%.  Found :  C,  73.0% ;  H,  4.5%. 

The  conversion  of  2'-hydroxy-flavone  into  salicylic  acid 
and  ortho-hydroxy-anisple. — St.  v.  Kostanecki  found  that  when 
an  hydroxy-flavone  derivative  is  heated  with  sodium  ethoxide, 
the  pyrone  ring  splits  at  the  double  bond  and  at  the  ether 
oxygen  with  the  formation  of  an  ortho-hydroxy-anisole,  and  a 
benzoic  acid  derivative.*  7 

When  2'-hydroxy-flavone  was  treated  with  sodium  eth- 
oxide, it  yielded  salicylic  acid  and  ortho-hydroxy-anisole — 
thus  proving  that  the  hydroxyl  group  occupies  the  2'  position 
in  the  flavone  nucleus. 

1.3  g.  of  2'-hydroxy-flavone  were  added  to  2.3  g.  of  sodium 
dissolved  in  40  cc.  of  ethyl  alcohol  and  the  solution  was  boiled 
under  a  reflux  condenser  for  two  hours.  The  mixture  was 
steam  distilled  to  remove  the  alcohol.  It  was  then  acidified 
with  a  slight  excess  of  hydrochloric  acid  and  steam  distilled 
again,  until  no  more  oil  came  over  (which  was  the  case  after 
ten  minutes).  10  cc.  of  concentrated  hydrochloric  acid  were 
added  to  the  hot  solution  (in  the  distilling  flask)  which,  on 
cooling,  deposited  long  white  needles.  After  another  crys- 
tallization from  hot  water  these  white  needles  melted  at  156°- 
157°  (corr.).  Yield=0.5  g.  This  compound  responded  to  the 

*  See  equation  III. 

24 


tests  for  salicylic  acid  with  ferric  chloride,  bromine  water  or 
methyl  alcohol  and  concentrated  sulphuric  acid. 

The  pale  yellow  oil  present  in  the  distillate  (above)  was 
extracted  with  ether.  The  ether  layer  was  separated  and 
treated  with  dilute  sodium  carbonate  in  order  to  remove  the 
small  amount  of  salicylic  acid  that  had  come  over  with  the 
steam.  The  ether,  after  evaporation  left  a  pale  yellow  oil  (of 
a  characteristic  aromatic  odor),  which  gave  an  intense  violet 
color  with  ferric  chloride.  This  oil  was  proven,  by  conversion 
to  its  phenyl  hydrazone,  to  be  ortho-hydroxy-anisole : — 

To  a  solution  of  the  oil  in  5  cc.  of  glacial  acetic  acid  was 
added  0.7  g.  of  phenyl  hydrazine  in  3  cc.  of  glacial  acetic  acid. 
The  mixture  was  warmed  for  ten  minutes.  On  the  addition 
of  5  cc.  of  water,  a  white  precipitate  came  down.  This  was 
filtered  and  recrystallized  once  from  dilute  alcohol.  Small, 
fine,  shining  white  needles  were  obtained.  M.P.  108°-108.5° 
(corn).  Tahara16  gives  108°. 

Subs.  0.2512:  N,  27.3  cc.  at  17°,  754  mm.    Calc.  for  Oi4Hi4ON2:  N, 
12.4%.    Found:  N,  12.5%. 

The  conversion  of  3'-hydroxy-flavone  into  meta-hydroxy- 
benzoic  acid  and  ortho-hydroxy-anisole — was  accomplished 
with  sodium  ethoxide  and  ethyl  alcohol  (as  above).  The  meta- 
hydroxy-benzoic  acid  formed  melted  at  199°-200°  (corr.).  The 
ortho-hydroxy-anisole  was  identified  by  converting  it  to  its 
phenyl-hydrazone  (as  above)— M.P.  108°-108.5°  (corr.). 

The  conversion  of  4'-hydroxy~flavone  into  ortho-hydroxy- 
anisole  and  para-hydroxy-benzoic  acid — was  accomplished 
with  sodium  ethoxide  and  ethyl  alcohol  (as  above).  The 
para-hydroxy-benzoic  acid  formed  melted  at  208°-209°  (corr.). 
The  ortho-hydroxy-anisole  was  identified  by  converting  it  to 
its  phenyl-hydrazone  (as  above).— M.P.  108°-108.5°  (corr.). 

Flavone  (2')-azo-beta-naphthol — 1.5  g.  of  2'-amino-flavone 
were  heated  for  ten  minutes  with  3  cc.  of  concentrated  hydro- 
chloric acid  in  50  cc.  of  water,  in  order  to  convert  it  to  the 
hydrochloride.  To  this  mixture  at  0°-5°,  were  added  3.6  cc. 
of  sodium  nitrite  solution  containing  0.45  g.  of  sodium  nitrite 
(calculated  amount).  After  stirring  for  one-half  hour,  the 
amine-salt  had  completely  dissolved.  The  resulting  diazo-salt 
solution  was  added  to  0.9  g.  (calculated  amount)  of  beta- 
naphthol  dissolved  in  25  cc.  of  3  N  aqueous  sodium  hydroxide, 
at  0°-5°.  The  flocculent  red  precipitate  was  filtered  and  well 
washed  with  water.  The  moist  substance  was  crystallized 
once  from  glacial  acetic  acid,  and  tufts  of  hair-like  red-orange 
needles  were  obtained,  which  melted,  with  decomposition,  at 
265°-266.5°  (corr.)  to  a  dark  red  liquid.  Yield=2.0  g. 

Subs.  0.3101:  N,  19.6  cc.  at  18°,  761  mm.    Calc.  for  Q£Hi'6O3N2 :  N, 
7.1%.    Found :  N,  7.3%. 

The  compound  dissolves  in  cold  concentrated  sulphuric 
acid  forming  a  reddish  purple  solution.  Is  readily  soluble  in 

25 


hot  concentrated  hydrochloric  acid,  and  slightly  so  in  cold 
concentrated  hydrochloric  acid  or  nitric  acid,  forming  cherry- 
red  solutions.  Is  insoluble  in  hot  or  cold  dilute  or  concen- 
trated aqueous  sodium  hydroxide.  Is  moderately  soluble 
(forming  orange-red  solutions)  in  hot  glacial  acetic  acid,  ethyl 
alcohol,  benzene,  or  acetic  anhydride.  Is  easily  soluble  in  hot 
amyl  alcohol  (technical)  or  chloroform.  Is  slightly  soluble 
in  ligroin ;  and  insoluble  in  cold  or  boiling  water. 

Flavone  (2')-azo-beta-naphthol  is  assumed  to  possess  the 
usual  ortho-quinone-imide  configuration  (with  the  nitrogen 
attached  to  the  naphthalene  ring  on  the  alpha-1  position)  which 
results  on  coupling  a  diazonium  salt  with  beta-naphthol.  (See 
structure  II.)  The  two  isomers  of  this  compound,  which  are 
described  below,  are  assumed  to  have  similar  configurations. 
(See  structures  III  and  IV.) 

Flavone (3 ')-azo-beta-naphthol. — 1.5  g.  of  3'-amino-flavone 
were  carried  thru  a  procedure  similar  to  that  described 
in  the  previous  experiment.  The  flocculent  red  precipitate 
resulting  was  crystallized  once  from  glacial  acetic  acid.  Small, 
flat,  shining  crimson  prisms  were  obtained.  The  compound 
assumed  a  metallic  lustre  at  253°  and  melted,  with  decomposi- 
tion at  257°  (corr.)  to  a  dark  red  liquid.  Yield=:2.1  g. 

Subs.  0.2781:  N.  17.6  cc.  at  19°,  755  mm.    Calc.  for  CasHieOs^:  N, 
7.1%.    Found:  N,  7.2%. 

The  compound  dissolves  in  cold  concentrated  sulphuric 
acid,  forming  a  deep  wine-red  solution.  Is  readily  soluble  in 
hot  concentrated  hydrochloric  acid,  and  slightly  so  in  cold 
concentrated  hydrochloric  or  nitric  acid,  forming  cherry-red 
solutions ;  insoluble  in  hot  or  cold,  dilute  or  concentrated 
aqueous  sodium  hydroxide.  Is  moderately  soluble  in  hot  glac- 
ial acetic  acid  or  acetic  anhydride;  also  slightly  soluble  in 
hot  ethyl  alcohol,  benzene,  chloroform,  amyl  alcohol  or  ligroin 
(100°-110°)  ;  and  insoluble  in  cold  or  boiling  water. 

Flavone  (4')-azo-beta-naphthol. — Proceeding  as  above,  1.5 
g.  of  4'-amino-flavone  gave  a  dark  red  flocculent  precipitate 
which  was  crystallized  once  from  glacial  acetic  acid.  Radiat- 
ing masses  of  small  dark  red  needles  were  obtained  which 
melted,  'with  decomposition,  at  274°-275°  (corr.)  to  a  dark 
red  liquid.  Yield=2.0  g. 

Subs.  0.3112:  N,  19.4  cc.  at  17°,  765  mm.  Calc.  for  C25Hi6O3N2:  N, 
7.1%.  Found:  N,  7.2%. 

The  compound  dissolves  in  cold  concentrated  sulphuric 
acid,  forming  a  deep  purple  solution.  Is  readily  soluble  in  hot 
concentrated  hydrochloric  acid,  and  slightly  so  in  cold  con- 
centrated hydrochloric  or  nitric  acid,  forming  deep  purple  solu- 
tions. Is  insoluble  in  cold  or  hot,  dilute  or  concentrated 
aqueous  sodium  hydroxide.  Is  easily  soluble  (forming  a  dark 
red  solution)  in  hot  chloroform  or  amyl  alcohol  (technical). 
Is  moderately  soluble  in  hot  benzene  or  acetic  anhydride ;  also 

26 


slightly  soluble  in  hot  ethyl  alcohol  or  ligroin  (100°-110°)  ; 
and  insoluble  in  cold  or  boiling  water. 

Application  of  the  Flavone-azo-beta-naphthol  dyes  to  silk, 
wool  and  cotton. — Silk,  wool  and  cotton  skeins  were  dyed  by 
developing  the  colors  directly  on  the  fibre.  Good  results  were 
obtained  with  silk  and  wool,  but  the  cotton,  even  when  pre- 
viously impregnated  with  Turkey  Red  Oil,  in  all  cases  took  the 
dyes  unevenly. 

Inferior  shades  were  obtained  by  passing  the  skeins  first 
thru  a  solution  of  the  diazo  salt  and  then  thru  an  alkaline  beta- 
naphthol  bath.  But  when  the  order  was  reversed  and  the 
goods  impregnated  first  with  the  alkaline  beta-naphthol  solu- 
tion and  then  passed  thru  the  diazo-salt  bath  in  which  the 
hydrogen, ion  concentration  from  the  excess  of  hydrochloric 
acid  had  been  reduced  by  the  addition  of  sodium  acetate,18  good 
dyeings  were  obtained. 

From  flavone  (2')-azo-beta-naphthol,  a  bright  orange  color 
was  obtained  on  silk,  and  a  duller  shade  of  orange  on  wool. 
Similar  colors  on  silk  and  wool  were  obtained  with  flavone 
(3')-azo-beta-naphthol.  With  flavone  (4')-azo-beta-naphthol, 
however,  a  bright  red  color  was  formed  on  silk  and  a  less 
bright  red  shade  on  wool. 

The  fastness  to  light  of  the  dyed  materials  was  determined 
by  exposing  them  in  the  north  window  of  the  laboratory. 
After  a  month's  exposure  (up  to  the  time  of  this  writing),  a 
comparison  with  some  of  the  unexposed  dyed  materials  showed 
that  no  change  in  shade  had  been  effected  in  any  case. 

The  dyed  silk  and  wool  samples  were  found  to  be  very 
resistant  to  the  action  of  the  alkali,  the  shades  not  being  af- 
fected by  hot  soap  solution  or  3%  aqueous  sodium  carbonate. 
In  all  cases,  however,  a  2%  acetic  acid  solution  caused  a 
dullening  in  the  shades. 

The  "exhaustion"  of  the  diazo  baths  was  more  rapid  with 
wool  than  with  silk.  It  was  found  that  when  a  number  of 
skeins  of  silk  of  equal  weight,  impregnated  with  alkaline  beta- 
naphthol,  were  successively  worked  in  the  same  solution  of 
diazo  salt  (which  initially  contained  5%  of  diazo  salt  on  the 
weight  of  one  skein  of  silk),  the  second  sample  possessed  a 
slightly  less  bright  shade  than  the  first;  the  third,  however, 
was  very  much  lighter  in  shade  than  the  first  two.  In  the 
case  of  wool  samples,  which  were  treated  in  a  similar  manner, 
there  was  as  great  a  difference  between  the  shades  of  the  first 
and  second  samples  as  between  the  first  and  third  dyeings 
on  silk. 

III. 

Beta-brom-hydrocinnamic  acid.  C6H5.CHBr.CH2,COOH. 
— was  prepared  as  described  by  Anschutz  17,  by  the  interaction 

27 


of  cinnamic  acid  and  hydrogen  bromide  in  glacial  acetic  acid. 
Two  crystallizations  of  the  crude  product  from  benzene,  gave 
white  shining  plates.  M.P.  133°-135°  (rate  of  heating  was  5 
degrees  per  minute). 

Methyl-beta-brom-cinnamate  C6H5CHBr.CH2.COOCH3— 
This  ester,  which  has  not  been  prepared  before,  was  syn- 
thesized for  use  in  a  reaction  carried  out  in  connection  with 
the  synthesis  of  beta-phenoxy-hydrocinnamic  acid  (q.v.).  It 
was  obtained  by  the  esterification,  with  dry  hydrogen  bromide 
and  ethyl  alcohol,  of  beta-brom-hydrocinnamic  acid. 

50  g.  of  beta-brom-hydrocinnamic  acid  were  dissolved  in 
125  cc.  of  methyl  alcohol,  and  the  resulting  solution  was  satu- 
rated with  dry  hydrogen  bromide  gas  at  room  temperature. 
After  standing  over  night,  the  mixture  was  poured  into  ice 
water.  The  faint  yellow  oil  that  separated  was  extracted 
with  petroleum  ether  and  the  ether  layer  was  mixed  with 
anhydrous  calcium  chloride  and  calcium  carbonate  and  allowed 
to  stand  over  night.  After  filtering,  half  of  the  petroleum 
ether  was  evaporated,  and  the  remaining  solution,  after  stand- 
ing in  the  ice  box  for  a  few  hours,  deposited  large  colorless 
thick  prisms.  M.P.  37.5°-38.5°  (corr.).  Yield=33  g. 

Subs.    0.3114:    AgBr,    0.2399.    Calc.    for    Ci0HiiO2Br:    Br,    32.9%. 
Found:  Br,  32.8%. 

The  compound  is  very  soluble  in  cold  chloroform,  benzene, 
carbon  disulfide,  carbon  tetrachloride,  glacial  acetic  acid,  tolu- 
ene, ether  or  acetone.  It  is  moderately  soluble  in  cold  pe- 
troleum ether,  ethyl  ether,  or  ligroin  (100°-110°). 

Beta-phenoxy-hydrocinnamic  acid  C6H5CH(OC6H5).CH2. 
COOH — was  synthesized  by  the  action  of  phenol  on  beta- 
brom-hydrocinnamic  acid. 

Two  other  products,  beta-phenyl-hydrocoumarin  and  beta- 
para-hydroxy-phenyl-hydrocinnamic  acid  were  also  formed  in 
this  reaction.  The  latter  two  compounds  have  been  previously 
synthesized  by  the  reaction  of  phenol  and  allo-cinnamic  acid  13. 

30  g.  of  beta-brom-hydrocinnamic  acid  were  added  to  a 
solution  of  13  g.  dry  phenol  (calculated  amount=12.3  g.)  in 
50  cc.  of  dry  benzene.  The  mixture  was  heated  and  the  acid 
dissolved.  The  temperature  of  the  solution  was  maintained 
at  85°-90°  for  two  hours  until  the  evolution  of  hydrogen 
bromide  had  slackened.  A  small  amount  of  water  had  col- 
lected below  the  cherry-red  benzene  layer.  On  cooling,  the 
benzene  solution  deposited  a  white  precipitate.  This  was 
filtered,  washed  twice  with  cold  benzene  and  dried  in  the  air. 
The  product  smelled  strongly  of  phenol.  It  weighed  12  g. 
Two  crystallizations  from  benzene  gave  10.4  g.  of  matted 
long  white  silky  needles.  M.P.  150°-151°  (corr.).  Yields 
33%  of  the  amount  calculated  from  the  beta-brom-hydrocin- 
namic acid. 

28 


Subs.   0.1424:    CO2,   0.3880;    H2O,   0.0770.     Calc.    for    Ci5Hi4O3:    C, 
74.470;  H,  5.8%.    Found:  C,  74.2%;  H,  6.0%. 

The  compound  is  soluble  in  dilute  sodium  carbonate  solu- 
tion. It  does  not  contain  a  double  bond  as  is  proven  by  its 
inability  to  decolorize,  in  the  cold,  potassium  permanganate. 
It  does  not  respond  to  any  of  the  tests  for  the  phenolic 
hydroxyl  group.  It  does  not  contain  bromine. 

The  empirical  formula  of  the  compound,  its  properties, 
and  its  method  of  formation  prove  it  to  be  beta-phenoxy-hydro- 
cinnamic  acid. 

Precipitates  were  formed  on  the  addition  of  a  solution  of 
the  ammonium  salt  of  beta-phenoxy-hydrocinnamic  acid  to 
solutions  of  the  nitrates  of  each  of  the  following  metals  re- 
spectively;— cadmium,  copper  (cupric),  lead  and  silver.  No 
precipitates  were  formed  with  the  following  metals : — sodium, 
potassium,  calcium,  barium,  bismuth,  cobalt  or  iron  (ferric). 

The  isolation  of  beta-para-hydroxy-phenyl-hydrocinnamic 
acid — The  benzene  filtrate  from  the  precipitate  of  beta-phe- 
noxy-hydrocinnamic acid  (above)  was  steam  distilled  and  a 
mixture  of  benzene  and  phenol  came  over.  The  phenol  was 
isolated  from  the  distillate  by  separating  the  benzene  from  the 
water  layer,  extracting  the  water  layer  with  ether,  combining 
the  benzene  and  ether  layers,  extracting  the  benzene-ether 
solution  with  aqueous  sodium  carbonate  (to  remove  some 
free  acid),  drying  the  ether-benzene  solution  with  calcium 
chloride,  filtering,  evaporating  off  the  ether  and  benzene,  and 
finally  distilling  the  yellow  oil  remaining.  1.5  g.  of  phenol, 
distilling  at  185°-187°,  were  thus  obtained.  This  amount  is 
0.8  g.  more  than  the  excess  of  phenol  which  was  used  in  the 
above  reaction — thus  showing  that  the  reaction  had  not  been 
complete  with  regard  to  the  phenol. 

The  brown  viscous  oil  in  the  distilling  flask  was  dissolved 
in  ether  and  extracted  with  dilute  sodium  carbonate  until  no 
more  carbon  dioxide  was  evolved.  The  water  layer  was  sepa- 
rated and  on  acidification  with  dilute  hydrochloric  acid,  a  white 
precipitate  came  down. 

Some  of  this  white  precipitate,  dissolved  in  aqueous  so- 
dium carbonate,  reduced  permanganate  solution  with  the  pro- 
duction of  an  odor  of  benzaldehyde,  which  indicated  the  pres- 
ence of  cinnamic  acid  (this  was  doubtless  formed  by  decomposi- 
tion of  part  of  the  beta-brom-hydrocinnamic  acid  into  cinnamic 
acid  and  hydrogen  bromide  in  the  above  phenol  and  beta- 
brom-hydrocinnamic  reaction).  The  white  precipitate  how- 
ever, contained  another  substance  which  was  separated  in  pure 
form  from  the  cinnamic  acid  by  four  recrystallizations  from 
toluene.  1.4  g.  of  white  needles  were  obtained.  M.P.  151.5°- 
152.5°  (corr.).  A  mixture  of  the  compound  with  beta-phe- 
noxy-hydrocinnamic acid,  melted  at  117°-126°,  which  proved 
that  it  was  not  beta-phenoxy-hydrocinnamic  acid. 

29 


Subs.   0.2561:    CGfc,   0.6975;    H*O,   0.1373.    Calc.    for   CisH^Os:    C, 
74.4%;  H,  5.8%.    Found:  C,  74.3%;  H,  6.0%. 

The  compound  is  soluble  in  aqueous  sodium  carbonate. 
It  responds  to  tests  for  the  phenolic  hydroxyl  group  with  con- 
centrated sulphuric  acid  and  sodium  nitrite,  and  with  titanium 
dioxide  in  concentrated  sulphuric  acid.  It  does  not,  however, 
give  a  color  reaction  with  ferric  chloride.  It  contains  no 
bromine. 

The  compound  is  believed  to  be  identical  with  beta-para- 
hydroxy-phenyl-hydrocinnamic  acid,  which  was  previously  iso- 
lated by  Liebermann  13,  and  with  which  it  agrees  in  its  em- 
pirical formula  and  properties. 

A  solution  of  the  ammonium  salt  of  beta-para-hydroxy- 
phenyl-hydrocinnamic  acid,  produced  precipitates  when  added 
to  solutions  of  the  nitrates  of  each  of  the  following  metals, 
respectively :— cadmium,  cobalt,  lead  or  silver.  No  precipitate 
was  formed  with  sodium,  potassium,  calcium,  barium,  bismuth, 
copper  (cupric)  or  iron  (ferric). 

The  formation  in  the  above  reaction,  of  beta-para-hydroxy- 
phenyl-hydrocinnamic  acid,  may  be  regarded  as  a  simple 
metathesis  between  phenol  and  beta-brom-hydrocinnamic  acid, 
thru  the  para  hydrogen  atom  of  phenol  and  the  bromine  atom 
of  the  acid  *. 

Isolation  of  beta-phenyl-hydrocoumarin. — The  ether  layer, 
from  which  the  beta-para-hydroxy-phenyl-hydrocinnamic  and 
cinnamic  acids  were  extracted  with  sodium  carbonate  (above), 
was  evaporated  and  a  yellow  oil  remained  which,  on  stirring, 
solidified  to  a  crystalline  mass  (12  g.).  Two  crystallizations 
from  alcohol  gave  thick,  white,  shining  needles.  M.P.  81.5°- 
82°  (corr.).  Yield=8.2  g. 

Subs.   0.1550:    CO2,   0.4642;    H2O,   0.0873.    Calc.    for   Ci'5Hi2O2:    C, 
81.6%;  H,  6.3%.    Found:  C,  81.7%;  H,  6.3%. 

The  compound  is  insoluble  in  cold  aqueous  sodium  car- 
bonate, and  only  partially  so  in  the  same  boiling  solvent.  It 
is  insoluble  in  cold,  and  easily  soluble  in  hot  dilute  sodium 
hydroxide  solution.  On  acidification  of  the  sodium  hydroxide 
solution,  a  white  precipitate  comes  down.  This  white  precipi- 
tate is  soluble  in  cold  sodium  carbonate  solution. 

The  compound  distills  at  243°  (uncorr.)  at  40  mm.  pres- 
sure. Liebermann  gives  237°  (uncorr.)  at  30  mm.  The  color- 
less oil  that  comes  over  quickly  solidifies  in  the  condenser  tube 
as  white  needles.  M.P.  81°-81.5°  (corr.). 

The  compound  is  believed  to  be  identical  with  beta- 
phenyl-hydrocoumarin,  which  was  first  isolated  by  Lieber- 
mann 13,  and  with  which  it  agrees  in  its  empirical  formula 
and  properties. 

*  See  equation  IV. 

30 


The  formation,  in  the  above  reaction,  of  beta-phenyl-hy- 
drocoumarin  may  be  regarded  as  proceeding  by  the  initial 
methathesis  between  phenol  and  beta-brom-hydrocinnamic 
acid,  thru  the  ortho  hydrogen  atom  of  phenol  and  the  bromine 
atom  of  the  acid,  to  form  an  intermediate  compound,  beta- 
ortho-hydroxy-phenyl-hydrocinnamic  acid,  which  immediately 
condenses  to  form  beta-phenyl-hydrocoumarin  with  elimina- 
tion of  water.*  The  observed  formation  of  water  in  the  above 
reaction  is  in  accord  with  this  explanation. 

Comments — In  an  attempt  to  obtain  a  better  yield  of  beta- 
phenoxy-hydrocinnamic  acid,  phenol  was  heated  with  methyl 
beta-brom-hydro-cinnamate ;  but  the  greater  part  of  the  phenol 
was  recovered  unchanged,  and  most  of  the  methyl-brom-hy- 
drocinnamate  was  found  to  have  decomposed  into  methyl  cin- 
namate  and  hydrogen  bromide.  Only  a  small  amount  of  beta- 
phenoxy-hydrocinnamic  acid  (isolated  by  the  saponification  of 
its  methyl  ester  which  was  formed)  was  obtained. 

Beta-brom-hydrocinnamic  acid  when  treated  with  potas- 
sium phenolate  gave  only  cinnamic  acid  and  styrol. 

The  barium  salt  of  a  disulfonic  acid  of  beta-phenoxy-hy- 
drocinnamic  acid.— [C6H3(SO3)2.CH(OC6H5).CH2.COO]2  Ba3. 
5.5H2O. — It  was  considered  probable  that  beta-phenoxy- 
hydrocinnamic  acid,  by  the  dehydrating  action  of  concentrated 
sulphuric  acid,  would  be  converted  into  flavanone.**  It  was 
found,  however,  that  a  disulfonic  acid  derivative  of  beta-phe- 
noxy-hydrocinnamic  acid  was  formed  instead.  This  disulfonic 
acid  was  isolated  in  the  form  of  its  hydrated  barium  salt. 

6.7  g.  of  beta-phenoxy-hydrocinnamic  acid  were  added  to 
60  g.  of  concentrated  sulphuric  acid,  heated  to  130°-135°,  and 
immediately  dissolved  with  the  formation  of  a  pale  yellow 
solution.  The  mixture  was  maintained  at  the  above  tempera- 
ture for  one  minute  (no  odor  of  sulphur  dioxide  was  per- 
ceptible) and  then  poured  into  ice.  Added  120  g.  of  solid 
barium  carbonate  (calculated  amount  for  60  g.  of  sulphuric 
acid)  and  filtered  the  neutral  solution.  Evaporated  the  filtrate 
to  dryness.  Extracted  the  yellow  solid  residue  with  hot  alco- 
hol. The  alcohol  dissolved  the  yellow  impurity,  leaving  a 
white  crystalline  solid. 

The  alcohol  solution  was  evaporated  and  a  slight  amount 
of  a  yellow  oil  was  left.  This  oil  was  very  soluble  in  water, 
gave  an  intense  purple  color  with  ferric  chloride,  reduced 
potassium  permanganate  in  the  cold,  and  gave  a  purple  color 
in  hot  aqueous  sodium  hydroxide.  Not  enough  of  the  oil  was 
available  for  further  investigation. 

The  white  barium  salt,  after  the  above  alcohol  treatment, 
was  recrystallized  three  times  from  water  and  ethyl  alcohol. 

*  See  equation  V. 

**  According  to  equation  I. 

31 


A  white  flocculent  precipitate  was  obtained.  Under  the  micro- 
scope this  precipitate  was  seen  to  consist  of  thin  broad  ir- 
regular plates.  The  precipitate  was  filtered  and  dried  over 
sulphuric  acid.  Yield=4  g. 

Subs.  0.4600:  H^O  lost  at  100°-110°,  0.0352;  BaSO4  02461  Calc 
for  QjoH22Oi8S4Ba3.5.5H2O :  H2O,  7.57%.  Found :  H<A  7.65%.  Calc. 
for  CsoH^OisSiBaa:  Ba,  34.00%.  Found:  Ba,  34.04%. 

A  solution  of  the  barium  salt  produced  precipitates  when 
added  to  solutions  of  the  nitrates  of  each  of  the  following 
metals,  respectively:  bismuth,  chromium  (chromic),  cobalt, 
silver,  or  tin  (stannic).  No  precipitates  were  formed  with: — 
sodium,  potassium,  calcium,  barium,  aluminum,  cadmium,  cop- 
per (cupric),  iron  (ferric),  lead,  magnesium,  manganese,  mer- 
cuy  (mercuric)  nickel,  or  zinc. 

The  same  sulfonic  acid,  as  above,  was  formed  when  beta- 
phenoxy-hydrocinnamic  acid,  dissolved  in  cold  concentrated 
sulphuric  acid,  was  allowed  to  stand  for  three  days. 

An  attempt  was  made  to  convert  the  acid  chloride  of  beta- 
phenoxy-hydrocinnamic  acid  into  flavanone  by  treating  it  with 
anhydrous  aluminum  chloride,  with  the  expectation  of  causing 
an  internal  condensation  by  the  elimination  of  hydrogen  chlo- 
ride * — in  analogy  to  the  formation  of  flavone  from  beta-phe- 
noxy-cinnamyl-chloride  2 : — 

Beta-phenoxy-hydrocinnamic  acid  in  benzene,  was  easily 
converted  to  its  acid  chloride  by  phosphorus  pentachloride. 
The  phosphorus  oxychloride  was  removed  from  the  acid 
chloride  by  distillation  in  vacuo.  The  remaining  acid  chloride 
in  benzene  solution  gave  no  reaction,  at  room  temperature,  on 
the  addition  of  anhydrous  aluminum  chloride ;  but,  on  heating, 
a  slow  evolution  of  hydrogen  chloride  took  place  and  a  brown 
amorphous  mass  separated  from  the  benzene.  The  brown 
mass  was  insoluble  in  water  and  in  nearly  all  of  the  organic 
solvents.  From  hot  chloroform  it  precipitated  in  an  amor- 
phous condition  (M.P.  141°-196°),  and  was  found  to  contain 
aluminum  from  which  it  could  not  be  separated. 

Finally,  attempts  were  made  to  effect  the  condensation  of 
beta-phenoxy-hydrocinnamic  acid  to  flavanone  with  other 
(than  sulphuric  acid)  dehydrating  agents : — 

Phosphorous  pentoxide  gave  no  reaction  in  the  cold,  and 
a  charred  mass  when  the  temperature  was  raised.  Fuming 
stannic  chloride  or  anhydrous  zinc  chloride  and  acetic  anhy- 
dride, even  when  heated  for  many  hours  with  the  acid,  likewise 
were  unsuccessful  in  bringing  about  the  desired  condensation. 

2-Nitro-Flavanone — was  synthesized  directly  by  the  action 
of  para-nitro-phenol  on  beta-brom-hydrocinnamic  acid. 

25  g.  of  beta-brom-hydrocinnamic  acid  and  15.5  g.  of  para- 
nitro-phenol  (calculated  amount  15.1  g.)  were  mixed  with  30 

*  According  to  equation  VI. 

32 


cc.  of  dry  benzene  in  a  flask  with  a  reflux  condenser,  and 
heated  at  80°-85°.  The  solids  dissolved,  and  a  copious  evo- 
lution of  hydrogen  bromide  lasted  for  fifteen  minutes.  The 
heating  was  continued  for  thirty  minutes.  The  solution  had 
become  dark  green  and  about  1  cc.  of  water  had  collected 
below  the  benzene  layer.  Distilled  off  the  benzene  and  water 
in  vacuo.  Weight  of  the  solid  residue=40  g.  Added  the 
crude  product  to  700  cc.  water  containing  12  g.  of  sodium 
hydroxide,  and  heated  on  the  water  bath.  The  greater  part 
of  the  solid  dissolved  to  a  yellow  solution,  leaving  a  small 
amount  of  an  heavy  black  oil  which  solidified  in  the  cold. 
The  black  solid  was  separated  by  filtration,  washed  with  water, 
and  dried  over  sulphuric  acid.  Yield=1.5  g.  Three  crys- 
tallizations from  glacial  acetic  acid,  in  the  presence  of  bone- 
black,  gave  long  thin  white  silky  needles.  M.P.  144°-144.5° 
(corr.).  Yield=0.57  g.  or  2%  of  the  calculated  amount  from 
the  beta-brom-hydrocinnamic  acid. 

Subs.  0.0931:  N,  4.48  cc.  at  23°-768  mm.     Calc.  for  Ci5HnOiN:  N, 
5.2%.    Found :  N,  5.4%. 

The  compound  is  insoluble  in  cold  or  hot  dilute  or  con- 
centrated aqueous  sodium  carbonate  or  sodium  hydroxide.  It 
does  not  reduce  cold  alkaline  potassium  permanganate  solu- 
tion, and  even  in  the  boiling  condition  the  permanganate  solu- 
tion is  reduced  slowly.  This  indicates  the  absence  of  a  double 
bond  or  a  phenolic  hydroxyl  group. 

The  compound  is  easily  soluble  in  cold  chloroform  or 
concentrated  sulphuric  acid  (in  which  it  forms  a  yellow  solu- 
tion), and  in  hot  ethyl  alcohol,  benzene,  or  glacial  acetic  acid. 
It  is  slightly  soluble  in  hot  ligroin  (100°-110°)  ;  and  is  in- 
soluble in  cold  or  hot  water. 

From  its  empirical  formula,  its  properties  and  the  method 
of  its  formation,  the  compound  is  believed  to  be  2-nitro- 
flavanone.  The  course  of  its  formation  consists,  most  likely, 
of  the  initial  metathesis  between  para-nitro-phenol  and  beta- 
brom-hydrocinnamic  acid  to  form  an  intermediate  compound, 
beta-para-nitro-phenoxy-hydrocinnamic  acid,  which  immedi- 
ately undergoes  an  internal  condensation  with  the  elimination 
of  water.*  The  observed  formation  of  water  (above)  is  in 
accord  with  this  explanation. 

There  are  two  compounds,  of  the  same  empirical  formula 
as  2-nitro-flavanone,  whose  possible  formation  from  para-nitro- 
phenol  and  beta-brom-hydrocinnamic  acid  would  also  have 
resulted  in  the  production  of  water : — 

(1) — Beta-phenyl-5-nitro-hydrocoumarin  —  might  have 
been  formed  in  analogous  manner  to  beta-phenyl-hydrocou- 
marin  from  phenol  and  beta-brom-hydrocinnamic  acid  (q.v.). 
But  this  substance  would  be  soluble  in  sodium  hydroxide  solu- 

*  According  to  equation  II. 

33 


tion,  which  property  the  compound,  actually  obtained,  does 
not  possess. 

(2) — Beta-para-nitro-phenoxy-hydrindone — m  i  g  h  t  have 
been  formed  by  the  internal  condensation,  thru  the  hydrogen 
atom  of  the  unnitrated  phenyl  nucleus  and  the  carboxyl  group, 
of  beta-para-nitro-phenoxy  hydrocinnamic  acid  *  (assumed  as 
an  intermediate  product).  The  properties  (q.v.)  of  the  com- 
pound actually  obtained,  do  not  enable  us  to  decide  between 
the  hydrindone  or  the  flavanone  structure;  and  lack  of  a  suf- 
ficient quantity  of  the  compound  prevented  further  investiga- 
tion to  conclusively  establish  its  configuration.  The  following 
considerations,  however,  point  strongly  to  the  compound  being 
2-nitro-flavanone : — 

Beta-phenoxy-hydrocinnamic  acid,  in  the  presence  of  de- 
hydrating agents  like  hydrogen  bromide  or  concentrated  sul- 
phuric acid  did  not  form  either  flavanone  or  hydrindone  (q.v.). 
The  reason  for  this  is,  very  probably,  that  neither  of  the 
ortho  hydrogen  atoms  on  the  phenyl  or  phenoxy  nuclei  (of 
beta-phenoxy-hydrocinnamic  acid)  is  labile  enough  to  react 
with  the  carboxyl  group  to  form  water.  However,  in  beta- 
para-nitro-phenoxy-hydrocinnamic  acid  (from  para-nitro- 
phenol  and  beta-brom-hydrocinnamic  acid),  the  presence  of 
the  nitro  group  would  be  expected  to  render  more  labile  the 
hydrogen  atom  lying  in  the  meta  position  to  it  on  the  same 
benzene  ring,  and  thus  cause  the  flavanone  condensation. 

To  assume  the  formation  of  nitro-hydrindone  would  mean 
that  the  presence  of  the  nitro  group  on  the  benzene  ring  of  the 
phenoxy  group  (of  beta-para-nitro-phenoxy-hydrocinnamic 
acid)  renders  the  hydrogen  atom  of  the  far  removed  phenyl 
group  more  labile  than  the  hydrogen  atom  lying  with  it  (the 
nitro  group)  on  the  same  benzene  ring — which  is  not  plausible. 

The  sodium  hydroxide  filtrate  from  2-nitro-flavanone 
(above)  was  acidified  with  hydrochloric  acid  and  the  precipi- 
tate which  deposited  was  found  to  consist  of  unchanged  para- 
nitro-phenol  and  cinnamic  acid — thus  indicating  that,  con- 
current with  the  formation  of  2-nitro-flavanone,  the  greater 
part  of  the  beta-brom-hydrocinnamic  acid  had  decomposed  into 
cinnamic  acid  and  hydrogen  bromide. 

It  was  considered  probable  that  the  decomposition  of 
beta-brom-hydrocinnamic  acid  would  be  minimized  if  the  re- 
action between  it  and  para-nitro-phenol  were  carried  out  under 
pressure— with  the  consequence  that  more  beta-brom-hydro- 
cinnamic acid  would  be  available  for  interaction  with  the 
para-nitro-phenol.  It  was  found,  however,  that  no  increased 
yield  (over  that  obtained  at  atmospheric  pressure)  of  2-nitro- 
flavanone  resulted  when  the  reaction  was  carried  out  in  a 

*  According  to  equation  VII. 

34 


sealed  tube  at  temperatures,  which  varied  in  different  experi- 
ments from  80°  to  125°  C. 

It  was  found  that  the  interaction  of  beta-brom-hydro- 
cinnamic  acid  with  the  sodium  or  silver  salt  of  para-nitro- 
phenol  gave  styrol  and  cinnamic  acid,  and  no  beta-para-nitro- 
phenoxy-cinnamic  acid  or  2-nitro-flavanone. 

When  a  mixture  of  2,4-dinitro-phenol  and  beta-brom- 
hydrocinnamic  acid  was  heated  in  boiling  benzene  or  ligroin 
(100°-110°)  very  little  reaction  took  place.  But,  when  the 
solids  were  suspended  in  xylene  and  heated  at  120°-125°,  hy- 
drogen bromide  was  evolved  rather  freely.  An  examination 
of  the  reaction  mixture  showed  that  it  consisted  of  cinnamic 
acid  and  unchanged  dinitro-phenol.  No.  2,4-dinitro-flavanone 
(as  expected)  or  dinitro-phenoxy-hydrocinnamic  acid  was 
found  to  have  been  formed. 


35 


SUMMARY 

I — 2'-Aminoflavone,  3/-amino-flavone,  and  4'-amino-fla- 
yone  have  been  synthesized.  They  all  possess  a  yellow  color, 
in  contrast  to  the  corresponding  hydroxy  flavones  which  are 
white — thus  indicating  the  more  powerful  auxochromic  effect 
of  the  amino  group  over  that  of  the  hydroxyl  group  on  the 
flavone  nucleus.  Also,  4'-amino-flavone  displays  the  remark- 
able property  of  fluorescing  only  in  neutral  solvents  which 
contain  the  hydroxyl  group. 

II — A  fast  red  dye,  flavone  (4')-azo-beta-naphthol,  and 
two  fast  orange  dyes,  flavone  (2')-azo-beta-naphthol,  and 
flavone  (3')-azo-beta-naphthol  have  been  synthesized. 

Ill — 2-Nitro-flavanone  has  been  prepared  by  a  rapid  meth- 
od, altho  in  poor  yield. 

IV — Other  compounds  which  have  been  synthesized  for 
the  first  time  are : — 2'-hydroxy-flavone,  2'-acetoxy-flavone ;  2'- 
diacetyl-amino-flavone ;  3'-diacetyl-amino-flavone ;  4'-diacetyl- 
amino-flavone ;  beta-phenoxy-hydrocinnamic  acid,  the  barium 
salt  of  a  disulfo  derivative  of  beta-phenoxy-hydrocinnamic 
acid ;  and  methyl-beta-brom-hydrocinnamate. 


36 


BIBLIOGRAPHY 

1.  B.  37,2635 

2.  B.  46,2188 

3.  Soc.  83,1154 

4.  B.  33,2516 

5.  B.  34,1692 

6.  B.  37,2635;  31,1760;  33,333;  46,2188;  47,2229 

7.  B.  31,702 

8.  B.  37,2820;  32,331 ;  31,703;  34,1692;  33,2516 

9.  Soc.  45,172 

10.  Soc.  83,673 

11.  Soc.  77,985 

12.  B.  24,2582 

13.  J.A.C.S.  39,82 

14.  B.  25,1309 

15.  B.  11,1221;  A.  195,132 

16.  Synthetic  Dyestuffs  and  Intermediate  Products,  by  Cain 

and  Thorpe,  pg.  322. 

N.B.  A  resume  by  St.  v.  Kostanecki  of  his  work  on  fla- 
vones  up  to  1903  appears  in  the  Bulletin  de  la  Societe  Chimique 
—Vol.  30  (1903)  Supplement. 


37 


BIOGRAPHICAL 

Joseph  K.  Marcus  was  born  in  New  York  City  on  January 
28,  1894 ;  received  his  elementary  school  training  in  the  schools 
of  this  city  and  of  Waukegan,  Illinois ;  was  awarded  the  degree 
of  Bachelor  of  Arts  by  the  College  of  the  City  of  New  York 
in  February,  1914;  entered  Columbia  in  February,  1914;  was 
Laboratory  Assistant  in  chemistry  from  1914  to  1916  and 
Assistant  in  chemistry  from  1916  to  1918  at  Columbia  Uni- 
versity. 


38 


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